Riley S. Rees

Serum amyloid P component: its role in platelet activation stimulated by sphingomyelinase D purified from the venom of the brown recluse spider (Loxosceles reclusa).

Serum amyloid P component or serum amyloid protein is a ubiquitous, highly conserved glycoprotein whose function is unknown. Although the related pentraxin, C-reactive protein, is an acute phase reactant in man, there is no direct evidence that human serum amyloid protein is involved in an inflammatory response. Here we show that serum amyloid protein is required by sphingomyelinase D, the principal necrotic agent of the venom of Loxosceles reclusa, for the in vitro-activation of human platelets. Furthermore, this platelet activation is dependent upon the presence of only serum amyloid protein; no other plasma components are necessary. Secretion of [3H]-serotonin and aggregation of platelets are nearly maximal following incubation of the platelets with purified sphingomyelinase D (0.3 micrograms/ml) and 5 micrograms/ml pure serum amyloid protein in the presence of calcium. Since the platelets are no longer activated when this 10% physiologic amount of serum amyloid protein is omitted, serum amyloid protein is likely to have a role in the necrosis caused by brown recluse spider venom.

Carcinoma of the hand: a 20-year experience

We reviewed our 20-year experience with cutaneous carcinoma of the hand and identified 70 cases (basal cell 23%, squamous cell 77%). The documented risk factors included solar radiation, trauma, and irradiation. Lesions were treated surgically with amputation, excision, skin graft, or flap closure, and nonsurgically with cryosurgery, curettage, 5-fluorouracil, or irradiation. The recurrence was lower with surgical treatment (3%) than with nonsurgical (33%). Regional Iymphadenectomy was required in four patients for metastatic squamous cell carcinoma. Recurrence was greater (9%) and metastasis more common (38%) in patients with Marjolins type of secondary squamous cell carcinoma than with solar-induced lesions. Cause is an important factor in outcome and should be considered in initial treatment and long-term management.

Pleomorphic Adenoma of the Cervical Esophagus: A Rare Tumor

Pleomorphic adenoma of the esophagus is a rare tumor: less than 10 cases have been reported. These pleomorphic neoplasms are sessile and arise in the submucosal glands of the esophagus. Described in this report is the long-term follow-up of an additional case, in which the resection was reinforced with a pectoralis major muscle wrap.

Analysis of vesicle fluid following the sting of the lionfish Pterois volitans

Fluid aspirated from blisters following a lionfish (Pterois volitans) sting was analyzed utilizing combined capillary column gas chromatography and negative ion chemical ionization mass spectrometry. Analysis for prostaglandin F2 alpha demonstrated 16.91 ng/ml, for prostaglandin E2 0.143 ng/ml, for 6-keto-prostaglandin F1 alpha less than 0.1 ng/ml (nondetectable) and for thromboxane B2 1.65 ng/ml. Platelet aggregation studies showed that blister fluid caused aggregation of isolated platelets only, which was inhibited by heat treatment or by the presence of normal donor plasma.

Platelet activation stimulated by the toxin of the brown recluse spider requires serum amyloid P component, not C-reactive protein

PREVIOUS studies in our laboratory, published in this journal (REFS et al., 1988) implicated C-reactive protein (CRP) as a co-factor required for platelet activation induced by the toxin of the brown recluse spider . Isolated human platelets free from plasma proteins were activated to aggregate and secrete serotonin when incubated with the toxin, calcium and adult plasma . However, if umbilical cord plasma was substituted for adult plasma no detectable activation of platelets was observed. Furthermore, we reported that the addition of supraphysiologic concentrations of CRP enabled cord plasma to support the toxins effects on platelets . More recent data from our laboratory establishes that serum amyloid P component (SAP), not CRP, is most likely the protein required by the toxin to activate human platelets in vitro, since SAP could be used at physiological concentrations . The results described above for supraphysiologic concentrations of CRP were probably attributable to contaminating SAP. It is well recognized that SAP is a common contaminant in CRP purifications (PEPYs et al ., 1977). This possibility could not be directly confirmed for the CRP preparation used in our initial study, however, since the supplier (Difco, Detroit, MI) had discontinued its production . To our surprise, CRP obtained from other suppliers (Pierce, Rockford, IL, and Calbiochem-Behring, San Diego, CA) was unable to support platelet activation over a wide range of concentrations . No SAP contamination was observed in these CRP preps when analyzed by sodium dodecyl sulfate-polyacrylamide electrophoresis ; moreover, the SAP prep that supported platelet activation was also found to be pure. Others have shown that CRP and SAPare deficient in umbilical cord plasma compared to adult plasma (PEPYs et al., 1978). The cord plasma samples used in both our initial and all subsequent experiments were analyzed by a modified electroimmunoassay technique (LAURELL, 1972) and found to contain low levels of SAP (6.1 f5.0 pg/ml compared to 50f 18 ug/ml for adult plasma). When SAP was added to cord plasma to levels equivalent to that found in adult plasma, it then supported platelet aggregation and serotonin secretion as well as did adult plasma . Highly purified CRP, even at supraphysiologic levels, could not substitute for SAP in mediating toxin-induced platelet activation in cord plasma . In conclusion, we acknowledge and hope to have now clarified the apparent discrepancy in the data from our laboratory . Other investigators as discussed by DE BEER and PEPYs (1982) have experienced similar difficulties, in different experimental systems, when

Thallium distribution in ischemic skin flaps

Abstract Thallous chloride (T1-201) has been used as a myocardial imaging agent because it substitutes for potassium and is accumulated intracellularly in living cells via the membrane Na + -K + -ATPase pump. We have used T1-201 to study the N + -K + -ATPase pump in ischemic skin flaps raised in New Zealand white rabbits. Caudally based, 4 × 10-cm dorsal skin flaps ( N = 10) were raised and imaged with a gamma camera immediately, and 24 hr following injection of intravenous (iv) T1-201. Flap I was raised before T1-201 injection and flap II was raised after T1-201 injection. Subsequently, erythrocytes were labeled with (iv) stannous pyrophosphate and technetium (Tc-99m) pertechnetate and imaged with a technetium window immediately following flap elevation and again at 24 hr. Flap survival was 5.6 ± 1.1 cm and was comparable to fluorescein penetration 5.1 ± 1.2 cm. Immediate images of flap II showed uniform distribution of T1-201 while T1-201 localized in the proximal part of flap I. Labeled RBCs were present throughout both flaps. At 24 hr, thallium redistributed away from the distal end of flap II and labeled erythrocytes were present only in the proximal part of both flaps, which was consistent with flap survival and fluorescein penetration. These results ( N = 18) were confirmed by autoradiography and flap sections counted in the gamma counter from flaps excised immediately, 24 hr, and 5 days following flap elevation. These data suggest an abnormality of the Na + -Ka + -ATPase pump in ischemic skin flaps which occurs early and affects the distribution of T1-201.