D.L. Hill

Ontogeny of chorda tympani nerve responses to gustatory stimuli in the rat

Electrical activity (whole-nerve responses) of the chorda tympani nerve (CT) in rats at 2-110 days of age was recorded in response to chemical (0.5 M NaCl, 0.5 M LiCl, 0.5 M NH4Cl, 0.1 M citric acid) stimuli applied to the dorsal surface of the tongue. The CT of rats as young as two days of age was differentially responsive to the various chemical stimuli, and the responsiveness of the CT to 0.5 M NaCl and 0.5 M LiCl relative to 0.5 M NH4Cl increased between 20 and 34 days of age and again between 35 and 90 days of age. The responsiveness of the CT to 0.1 M citric acid relative to 0.5 M NH4Cl increased from 6--19 days of age, then decreased thereafter to adulthood. A concentration series of NH4Cl solutions (0.1 M, 0.25 M, 0.5 M and 1.0 M) revealed that the CT of rats 6--110 days of age displayed increased response magnitudes as the concentration of NH4Cl increased. The CT was responsive to mechanical and thermal stimulation of the tongue, and this responsiveness was essentially unchanged throughout development. These results show that the CT of rats as young as two days of age is differentially responsive to chemical stimuli applied to the tongue, and that CT responsiveness to chemical stimuli changes during development.

Intrafollicular cortisol levels inversely correlate with cumulus cell lipid content as a possible energy source during oocyte meiotic resumption in women undergoing ovarian stimulation for in vitro fertilization

OBJECTIVE To determine whether follicular fluid (FF) cortisol levels affect cumulus cell (CC) lipid content during oocyte meiotic resumption, and whether CCs express genes for glucocorticoid action. DESIGN Prospective cohort study. SETTING Academic medical center. PATIENT(S) Thirty-seven nonobese women underwent ovarian stimulation for in vitro fertilization (IVF). INTERVENTION(S) At oocyte retrieval, FF was aspirated from the first follicle (>16 mm in size) of each ovary and pooled CCs were collected. MAIN OUTCOME MEASURE(S) Follicular fluid cortisol and cortisone analysis was performed with the use of liquid chromatography-tandem mass spectrometry. CCs were stained with lipid fluorescent dye Bodipy FL C16 to determine lipid content with the use of confocal microscopy. Quantitative real-time polymerase chain reaction was used to detect CC gene expression of 11β-hydroxysteroid dehydrogenase (11β-HSD) types 1 and 2, glucocorticoid receptor (NR3C1), lipoprotein lipase (LPL), and hormone-sensitive lipase (HSL). RESULT(S) Adjusting for maternal age, FF cortisol levels negatively correlated with CC lipid content and positively correlated with numbers of total and mature oocytes. CCs expressed genes for 11β-HSD type 1 as the predominant 11β-HSD isoform, NR3C1, LPL, and HSL. CONCLUSION(S) FF cortisol levels may regulate CC lipolysis during oocyte meiotic resumption and affect oocyte quality during IVF.

Micromanipulation in a center for reproductive medicine

Several variations of micromanipulation of the female gamete (zona drilling, zona cracking, ooplasmic sperm injection, partial zona dissection) have been applied recently to human IVF to overcome severe male factor. Of the first 16 cycles attempted using partial zona dissection, one pregnancy resulted leading to a normal term delivery. Careful removal of the coronal cells, as well as stepwise removal of sucrose postpartial zona dissection, will facilitate this procedure and greatly reduce potential damage to the oocyte by pH, mechanical, or thermal injury. Micromanipulation has become a routine service offered in our program in cases where the likelihood of a poor IVF outcome is either known or suspected, and also serves as a replacement for simple reinsemination in cases of failed fertilization.

Cumulus Cell Mitochondrial Resistance to Stress In Vitro Predicts Oocyte Development During Assisted Reproduction

CONTEXT Complex cumulus cell-oocyte interactions govern energy utilization during oocyte development. OBJECTIVE This study investigates the relationship of cumulus cell mitochondria with oocyte development during ovarian stimulation for in vitro fertilization (IVF). DESIGN This is a prospective cohort study. SETTING The setting was an academic center. PATIENTS Thirty women underwent ovarian stimulation for IVF. INTERVENTION(S) Pooled cumulus cells were collected; numbers of total and mature oocytes and two-pronuclear (day 1), six- to eight-cell cleavage (day 3), and blastocyst (day 5) embryos were recorded. MAIN OUTCOME MEASURE(S) A mitochondrial bioassay was developed with Jurkat cells and used with cumulus cells from IVF patients to correlate mitochondrial membrane potential resistance to carbonyl cyanide 3-chlorophenylhydrazone (CCCP) stress with oocyte development and embryogenesis. RESULTS Adjusting for FSH administered and maternal age, cumulus cell mitochondrial membrane potential resistance to CCCP positively correlated with numbers of total (P < .025) and mature (P < .025) oocytes retrieved. The highest oocyte numbers that correlated with cumulus cell mitochondrial membrane potential occurred in women with the greatest ovarian response to FSH (mitochondrial membrane potential resistance to CCCP-log FSH interactions: total oocytes P < .025; mature oocytes P < .05). Multiple regression modeling of mature oocyte numbers, age, and cumulus cell mitochondrial membrane potential resistance to CCCP showed that numbers of mature oocytes best correlated with numbers of embryos at all stages (P < .0001). CONCLUSION During ovarian stimulation for IVF, cumulus cell mitochondrial membrane potential resistance to stress correlates with numbers of total and mature oocytes retrieved, suggesting that cumulus cell-oocyte interactions involving energy facilitate oocyte development.

Role of the in vitro fertilization laboratory in a negative pregnancy outcome

In June, couple R underwent their first attempt at IVF-ET. The semen analysis was normal, and the woman was a 37-year-old gravida 0 with a normal infertility workup, including an FSH level of 9 IU/L and a peak E2 level of 909 pg/mL at the time of hCG administration. Three days after retrieval, six embryos had developed, a 7-cell grade B, a 6-cell grade C, a 5-cell grade C, two 4-cell grade D, and one fragmenting grade D embryo (Fig. 1). Three of these embryos were transferred on day 3, and the remaining three were cryopreserved. A subsequent frozen embryo transfer with the remaining embryos resulted in a negative pregnancy test, the same outcome as resulted from the transfer of their fresh embryos. What, then, can be said about the effect the IVF laboratory may have had on these results?

Lateral hypothalamus destruction in infant rats produces consummatory deficits without sensory neglect or attenuated arousal

Abstract Male and female albino rats sustained bilateral electrolytic destruction of the lateral hypothalamic area (LHA) at 10 days of age. After brain damage, physical growth, the ontogeny of sensorimotor behavioral capacity, and consummatory behavioral responses to specific regulatory challenges were repeatedly and systematically assessed for as long as 375 days of age. Bilateral LHA damage caused immediate cessation of suckling from the dam and necessitated maintenance by hand and tube feeding. The infant LHA rats were incapable of regulating body weight by intake of dry food and water alone when killed at 70 or 375 days of age. Although they eventually could maintain body weight by ad libitum intake of highly palatable wet diets, these rats displayed severe body weight reduction, impaired linear growth, and permanent consummatory deficits to specific regulatory challenges. Multimodal sensorimotor tests failed to reveal “sensory neglect” or “attenuated arousal” in the brain-damaged rats; however, a transient syndrome of motor deficits and hyperreactivity consistently appeared. These findings were in sharp contrast to the sensorimotor deficits seen in animals which sustain LHA damage after weaning or in adulthood. These data argue that sensory neglect or attenuated arousal is not necessary to production of consummatory deficits and, taken with other research, suggest that damage to intrinsic LHA neurons causes consummatory deficits whereas damage to fibers of passage causes sensorimotor impairment.

Is Gender Selection an Appropriate Use of Medical Resources

Gender selection by PGD is an appropriate use of medical resources. Children borne through PGD for gender determination would be welcome and would come into a couples life at a planned, opportune time. If the practice were made more available through insurance coverage, the size and makeup of families could become a matter of choice rather than chance for couples favoring this approach.

Aneuploidy screening of preimplantation embryos using comparative genomic hybridization versus fluorescence in situ hybridization techniques.

When the results of comparative genomic hybridization (CGH) technology are compared with aneuploidy screening panels routinely run on fixed blastomeres using fluorescence in situ hybridization (FISH), it appears that CGH could act as an additional tool to determine which of a set of preimplantation embryos have a balanced karyotype. This information could lead to lower numbers of embryos transferred, potentially lowering multiple pregnancy outcomes. The CGH and FISH analyses can also be useful in explaining why some patients do not conceive after multiple embryo transfer attempts, which have added up to a total of two dozen or more embryos transferred to a single patient over successive transfers.

Midbrain reticular formation damage and the ontogeny of ingestive and sensorimotor behaviors.

Abstract Infant rats sustained bilateral electrolytic lesions of the midbrain reticular formation (MBRF) at 10 days of age. Growth measures and tests of sensorimotor, feeding, drinking, and gustatory capacities were made between 1 and 150 days of age. The MBRF rats displayed a transient period of attenuated suckling, as evidenced by body weight loss, and recovery of growth by the age of weaning. In conjunction with the period of altered growth, MBRF rats displayed some specific sensorimotor deficits and were extremely hyperactive. As adults, MBRF rats were hypodipsic during 24 hr food deprivation and after 24 hr water deprivation. On other drinking tests, feeding tests, and taste tests, MBRF rats responded at control levels. These results are comparable to the behavioral deficits displayed by rats sustaining MBRF damage as adults.

Damage to the ventromedial hypothalamic nucleus of newborn rats: growth, ingestion, and neuroendocrine dysfunction.

Abstract Newborn (24 ± 12 h postpartum) male or female albino rats sustained bilateral electrolytic destruction of the ventromedial hypothalamic nucleus (VMH) or sham surgery. Compared with same-gender controls, all rats with VMH damage had growth, behavioral, and endocrine dysfunctions with the following features: (i) mild body weight deficits until 70 to 80 days of age and permanently elevated body weights thereafter, (ii) progressive obesity after 50 days of age, (iii) ingestive finickyness, and (iv) reduced adenohypophyseal TSH cell (thyrotroph) density and number. The VMH-damaged females tended to have greater disorders than males. The VMH-damaged rats normal linear growth and ad libitum daily food intake from 30 to 200 days of age. In conjunction with previous research, these results support three conclusions: (i) deficits of the hypothalamic-pituitary-thyroidal axis are probable etiological factors in the developmental obesity of rats that sustain ventrobasal hypothalamic damage during infancy, (ii) the VMH is involved in the regulation of body weight and adiposity from the day of birth in the rat, and (iii) both neuroendocrine and behavioral functions of the rat VMH undergo significant postnatal modification.