Platelet adhesion to collagen types I through VIII under conditions of stasis and flow is mediated by GPIa/IIa (alpha 2 beta 1-integrin)

Platelet adhesion to fibrillar collagens (types I, II, III, and V) and nonfibrillar collagens (types IV, VI, VII, and VIII) was investigated in the presence of physiologic concentrations of divalent cations under conditions of stasis and flow. Under static conditions, platelet adhesion was observed to collagen types I through VII but not to type VIII. Under flow conditions, platelet adhesion to collagen types I, II, III, and IV was almost independent of shear rates above 300/s. Collagen type V was nonadhesive. Platelet adhesion to collagen type VI was shear rate-dependent and optimal at a rate of 300/s. Collagen types VII and VIII showed minor reactivity and supported platelet adhesion only between shear rates 100 to 1,000/s. Monoclonal antibody (MoAb) 176D7, directed against platelet membrane glycoprotein Ia (GPIa; very late antigen [VLA]-alpha 2 subunit), completely inhibited platelet adhesion to all collagens tested, under conditions of both stasis and flow. Platelet adhesion to collagen type III at shear rate 1,600/s was only inhibited for 85%. The concentration of antibody required for complete inhibition of platelet adhesion was dependent on the shear rate and the reactivity of the collagen. An MoAb directed against GPIIa (VLA-beta subunit) partially inhibited platelet adhesion to collagen. These results show that GPIa-IIa is a major and universal platelet receptor for eight unique types of collagen.     

Pseudoaneurysms complicating organ transplantation: roles of CT, duplex sonography, and angiography

In a retrospective study of proved pseudoaneurysms (PAs) in 15 patients with transplanted organs (11 liver, three kidney, one pancreas), the results of computed tomography (CT), duplex sonography, and angiography were reviewed. Of the 15 cases of PA, eight occurred at the arterial anastomosis and seven were nonanastomotic. Three of the eight anastomotic PAs were caused by infection. Of the seven nonanastomotic PAs, four were caused by percutaneous biopsy, two were caused by infection, and one was of undetermined cause. In nine (60%) of the 15 patients the PAs were incidentally detected at imaging studies performed for other reasons. Diagnosis requires a high degree of suspicion. CT was performed in nine cases and duplex sonography in ten. The diagnosis of PA was made with CT in six (67%) patients and with duplex sonography in five (50%). CT and duplex sonography could not enable diagnosis when the PA was small, when the arterial anastomosis was not included in the field of study, or when enhancement with intravenously administered contract material was suboptimal. Angiography depicted the PAs in all 15 patients. In three liver transplant recipients with gastrointestinal tract bleeding, the causative PAs were detected only with angiography.     

FK506 in combination with methotrexate for the prevention of graft- versus-host disease after marrow transplantation from matched unrelated donors

The safety and potential efficacy of FK506 in combination with a short course of methotrexate (MTX) for the prevention of acute graft-versus- host disease (GVHD) after marrow transplantation from HLA-matched unrelated donors was evaluated in a single-arm Phase II study conducted at two centers. Forty-three patients, 15 to 54 (median 41) years of age, were transplanted for hematologic malignancies. Thirty-seven of 43 evaluable patients had evidence of sustained marrow engraftment. Five patients died before day 17 after transplantation. The median time to an absolute neutrophil count of > 0.5 x 10(5)/L was 21 (range, 14 to 30) days. Nephrotoxicity (serum creatinine concentration > 2 mg/dL or doubling of baseline) occurred in 32 patients (74% cumulative incidence during the first 100 days after transplant). Other adverse effects included hypertension (n = 27), hyperglycemia (n = 27), neurotoxicity (n = 9) and thrombotic thrombocytopenic purpura (n = 2). Severe veno- occlusive disease of the liver occurred in 9 (21%) of the 43 patients. Eighteen patients (42%) developed grades II to IV acute GVHD and five (12%) developed grades III to IV acute GVHD. Twelve of 25 evaluable patients developed extensive chronic GVHD within 1 year of marrow transplantation resulting in an estimate of the probability of developing this complication of 48%. The cumulative incidence of transplant-related mortality during the first 100 days was 37%. Kaplan- Meier estimates of disease-free survival at 2 years for good-risk, poor- risk, and all patients were 65%, 4%, and 32%, respectively. FK506 in combination with a short course of MTX appears active in preventing acute GVHD after marrow transplantation from unrelated donors. Further studies comparing the combination of FK506 and MTX with cyclosporine and MTX for the prevention of acute GVHD are warranted.     

Spacing of cytochrome oxidase blobs in visual cortex of normal and strabismic monkeys

Some models of visual cortical development are based on the assumption that the tangential organization of V1 is not determined prior to visual experience. In these models, correlated binocular activity is a key element in the formation of visual cortical columns, and when the degree of interocular correlation is reduced the models predict an increase in column spacing. To examine this prediction we measured the spacing of columns, as defined by cytochrome oxidase (CO) blobs, in the visual cortex of monkeys whose binocular vision was either normal or disrupted by a strabismus. The spatial distribution of blobs was examined in seven normal and five strabismic macaques. Tangential sections through the upper layers of the visual cortex were stained to reveal the two-dimensional (2D) pattern of CO blobs. Each blob was localized and their center-to-center spacing, packing arrangement and density were calculated using 2D nearest-neighbor spatial analyses. The mean center-to-center spacing of blobs (590 microm for normally reared and 598 microm for strabismic macaques) and the mean density of blobs (3.67 blobs/mm2 for normally reared and 3.45 blobs/mm2 for strabismic macaques) were not significantly different. In addition, the 2D packing arrangement of the blobs was not affected by strabismus. While it is clear that neural activity plays a key role in the elaboration and refinement of ocular dominance cortical modules, we conclude that it does not determine the spatial period of the pattern of CO blobs. This suggests that aspects of the neural circuitry underlying the columnar architecture of the visual cortex are established prenatally and its fundamental periodicity is not modifiable by experience.      

Homicide by dual modality. A case report

A case of homicide by dual modality is presented. The intriguing involvement of a hired killer is described. Attention is drawn to the legal implications of the autopsy findings, as well as to the differing emphases placed on them by the defence counsel and the counsel for the prosecution. The forensic significance of the different injuries is discussed.     

Growth and proportionality in early childhood. I. Within population variations

Data on the postnatal growth patterns of 238 small-for-gestational age (SGA) and 241 large-for-gestational age (LGA) babies are presented. Three proportionality ratios were selected; and their changes in shape, by these indices, during the first 7 years are compared with a random sample of 284 children drawn from the same population. Highly significant differences (P less than 0.001) were found between the mean head-chest and head-length ratios for both sexes at birth; but mean chest-length ratios did not differ. Our findings show that these three measures of proportionality differ in their patterns of change over time; in the influence of birthweight group on their absolute values at each age; and the influence of sex within birthweight groups. At 7 years SGA children still had the highest and LGA children the lowest head-chest and head-stature ratios, and the differences were significant (P less than 0.01) for girls. This was mainly due to the relatively small heads of LGA girls. 46% of our sample had a head-chest ratio above unity at the age of 2 years. The "rule of thumb" criterion for the identification of malnourished children, based on the general principle that mean chest circumference overtakes head circumference by the age of 12 months, should not be too strictly applied.     

Management of Vascular Injuries in a Forward Hospital

Background

Management of vascular injuries poses a challenging problem under warlike conditions. Several authorities recommend limb revascularisation only within first 6-8 hours, as the outcome after delayed revascularisation is poor.

Methods

A retrospective analysis of 61 consecutive patients with vascular injury in a forward hospital over a 25- month period was carried out.

Results

Vascular injuries constituted 3.1% of all injuries. The mean injury to treatment delay (lag time) was 11 hours, and 10 patients received treatment after 12 hours. The overall amputation rate was 15%, but only 6.5% for those revascularised within 12 hours and 44% for those undergoing surgery after 12 hours (Chi-square 4.59, p < 0.05). Presence of associated fractures was associated with an adverse outcome (Chi-square 4.24, p < 0.05), as was ligation in comparison to revascularisation (Chi-square 7.86, p < 0.005). Popliteal injuries were associated with a high amputation rate.

Conclusions

Failure to revascularise (ligation of artery), presence of associated fracture, and restoration of circulation beyond 12 hours are associated with a high amputation rate.Key Words: Vascular injuries, trauma, amputation     

Parathyroid Neoplasms: The Army Hospital (Research & Referral) Experience

Background

Neoplasms of the parathyroid are common but parathyroid carcinoma is exceptionally rare. In contrast to most other malignant endocrine tumours that are usually less hormonally active, malignant parathyroid tumours are hyper functional. Malignant parathyroid tumours pose a diagnostic dilemma for the pathologist.

Objective

To study the clinicopathological profile of a case series of parathyroid neoplasms and determine features which facilitate a malignant diagnosis.

Methods

A retrospective analysis of seven cases of surgically treated parathyroid tumours over a three-year period at a single centre was done. Clinical, haematological, biochemical, and radiological data was accrued from medical records. The histopathology slides were reviewed along with the clinicopathological profile in an attempt to delineate markers of malignancy.

Results

Patients ranged from 30 to 58 years of age. Males and females were approximately equal. Weakness and bone pain were the commonest presenting symptoms. Over 50% had significant hypercalcaemia and all had elevated serum parathormone. Clinically apparent mass was seen in only one. All tumours were successfully localised using CT scan and MRI. Thick fibrous capsule and broad septal fibrosis was seen in both the carcinomas; these were thin in the adenomas. Mitotic counts of 1-3 per high power field (HPF), capsular invasion and nodal metastasis were noted in the malignant tumours.

Conclusion

Elevated serum calcium and parathormone values point to a parathyroid neoplasm. Current imaging modalities are successful in localising the tumour preoperatively. Markedly elevated serum calcium, broad fibrous bands, mitotic counts and capsular invasion are indicators of malignancy.Key Words: Parathyroid, Adenoma, Carcinoma