Mortimer Lorber

Measurements of Lacrimal Glands from Cadavers, With Descriptions of Typical Glands and Three Gross Variants

Objective: To measure cadaveric human lacrimal glands. Methods: Excised lacrimal glands from 22 male and 23 female embalmed cadavers were stored in embalming fluid. They were then blotted, weighed, and measured using dividers and a digital micrometer. Results: Besides the typical gland (Type I), three gross variants were found. The subencapsulated variant (Type II) has dense connective tissue covering its deep surface. This would prevent the usual horizontal positioning of the lobes relative to the levator palpebrae superioris aponeurosis (lpsa), causing the latter to extend but minimally beneath the free edge of the orbital lobe. Consequently, the gland lies mainly beside the globe and angulated parallel to the lpsa. Its adjacent palpebral lobe lies beneath the latter. The bilayered variant (Type III) has its smaller orbital lobes deep surface affixed above its large, ovoid palpebral lobe. Most of the gland droops beside the globe except for the edge of its orbital lobe which lies above the edge of the lpsa and beneath which the palpebral lobes anteromedial portion lies. The macrovariant (Type IV) resembles the typical gland. However, between its big lobes is an unusually large gape for the lpsa. Conclusions: Variant lacrimal glands are common (51.1%). Three types have been identified. The subencapsulated (26.7%) and bilayered (22.2%) types are the more common ones. Only one macrovariant (2.2%) specimen was found. Several dimorphisms exist in the typical and subencapsulated types, specimens from male cadavers being larger.

Somatostatin-Like Immunoreactivity (SLIR) in Rat Harderian and Meibomian Glands and Glands of Zeis

In many species serous lacrimal glands bind sex hormones and prolactin, have cells making immunoglobulins and growth factors, and contain nerve fibers having peptides such as VIP, NPY, and Substance P.1 Because the latter neuropeptides also occur in the sebaceous meibomian gland,2 the present study sought to determine the possible presence and cellular localization of somatostatin (SOM) in the three lipid-containing3, 4 lacrimal glands of the rat. Its existence might affect neuroendocrine-immune system interactions,5 presumably diminishing them because SOM inhibits lymphocyte proliferation.6

Circumstances favoring jaw tumors in Burkitt's lymphoma

In Burkitts lymphoma, dental structures may provide the route for Epstein-Barr virus (EBV) in saliva to penetrate the jaws, thereby promoting tumor formation. In children, EBV could enter tooth sockets exposed following deciduous tooth loss and thereby contact jaw marrow lymphocytes stimulating neoplastic transformation. Marrow contact by EBV probably also occurs through carious teeth. Jaw tumors are rare in adults because their jaw marrow is no longer hematopoietic and so lacks the lymphoid substrate for the virus. In adults, jaw marrow lymphocytosis, as accompanies infectious mononucleosis and perhaps malaria, or which could develop around the roots of carious teeth having chronic periapical infection, could provide the substrate for EBV. EBV could then contact the jaw marrow lymphocytes when teeth are extracted and so favor jaw tumor development. Therefore, prevention of dental caries might reduce jaw tumor prevalence in Burkitts lymphoma except among children ages 6-13 whose jaw marrow would unavoidably become infected by salivary EBV when the latter is present at the time of deciduous tooth loss.

WHEN IS DOUBLE‐BLIND DRUG EVALUATION IMPROPER?

This is to express some thoughts on one brief aspect of time excellent paper by Drs. Ryan amid Fisher.1 This aspect pertains to time question of ivhen a clinical trial should mmot be double-blind.2 This question deserves eommsideration mmow timat clinical trials are beimig mnade of antiviral drugs. These thoughts are applicable to theimm and to other drugs directed to time thmem-apy of diseases that are

The Splenic Hemogram of the Unanesthetized Dog.

Summary Splenic and venous blood samples were obtained in unanesthetized dogs whose spleens had previously been placed subcutaneously with their vascular supply essentially intact. Erythrocyte and reticulocyte levels are elevated in the spleen. Under pentobarbital, the relocated spleen has less of those cells than does the normal organ. Evidence was presented that diverse splenic functions such as sequestration of formed elements and distensibility are interfered with by placing the spleen between the relatively rigid skin and abdominal musculature of the dog.

Comments on the paper "synergistic effects of prostacyclin analogs and phosphodiesterase inhibitors on cyclic adenosine 3',5' monophosphate accumulation and adenosine 3'5' triphosphate release from human erythrocytes".

In the circulating blood, red cell ages vary from the youngest, the reticulocytes, which had left the bone marrow less than 24 h before, to the oldest whose age is about 120 days. Therefore, reticulocytes amount to about 0.8% of the circulating red cells. By staining all types of circulating blood cells using routine Wright staining or its variations, the youngest cells appear somewhat larger than mature red cells, and are polychromatophilic. The routinely employed specific staining method for reticulocytes uses New Methylene Blue. This stain demonstrates that within the reticulocyte population the cells vary in appearance. The youngest cells have a large amount of basophilic ribonucleoprotein, but have no nuclei from their preceding developmental stages within the bone marrow. Contrariwise, the most mature reticulocytes on the verge of becoming erythrocytes have but a single dot to identify their pre-erythrocytic state. Knebel et al., rather than washing circulating blood once in order to separate all of the erythrocytes from the other types of blood cells and plasma components, performed three centrifugations, each involving removal of its superficial red cells. The repeated centrifugations of blood followed by discarding the upper cells resulted in Knebel’s group having analyzed not the normal circulating red cell mass whose cells vary as just described. Consequently, their findings may not be applicable to the circulating blood. The cells approaching their terminal stage as reticulocytes are the older ones of this group which despite having less ribonucleoprotein are heavier, presumably because they contain more fetal hemoglobin. Despite that, the lesser density of all reticulocytes results in the layering of these cells on centrifugation above the mature erythrocytes. Consequently, I suggest that for more physiological results Knebel’s group repeat its studies so that circulating blood cells, which are of all ages, are washed by centrifugation. A single centrifugation should suffice to layer the buffy coat of leukocytes and platelets above the red blood cells. This is followed by precise use of a syringe and blunt needle to aspirate the well-demarcated buffy coat which is then discarded, leaving red cells of all ages available for analysis. This would avoid biasing their findings toward the older cells.

THE EXORBITAL LACRIMAL GLANDS OF THE RAT ARE TENSED IN SITU

The main lacrimal gland of rodents is a paired, extraorbital organ. Each exists subcutaneously anterior to and slightly below the ear. This study will demonstrate that this exorbital lacrimal gland exists under tension. This characteristic became manifest when we noted that the gland’s width and length diminished as its attachments were removed during excision. Were it not tensed, no such dimensional changes would have occurred as it was freed (Fig. 1).

The Parenchyma Accompanying Major Extraglandular Ducts within the Rat Lacrimal Cord

While investigating regional differences in the duct-containing cord joining the rat exorbital lacrimal gland and conjunctiva (Fig. 1A), it was noted that some specimens also contained small masses of parenchyma (Fig. 1B). This study is concerned with the distribution and histological appearance of this cordal lacrimal tissue.