Effect of Metabolic Control with Insulin on Plasma von Willebrand Factor Activity Growth Hormone, and Platelet Aggregation in Diabetes Mellitus

Elevated plasma von Willebrand factor activity (ristocetin method:VIIIR:WFj and high plasma growth hormone (GH) levels occur in diabetes mellitus. Hypersensitivity of plate lets to aggregating agents is also seen. We have therefore studied the effect of short-term diabetic control with insulin on plasma VIIIR:WF, GH, and platelet aggregation.

Tight metabolic control with insulin was instituted for two weeks in five insulin depend ent diabetic patients after a period of inadequate diabetic control. Overnight sleep studies were performed before and after the period of closely monitored insulin administration, and frequent determinations of plasma glucose, VIIIR:WF, and GH levels were done during sleep. Platelet aggregation thresholds to ADP, epinephrine, and arachid’lic acid were measured before and after tight control.

We found that: (1) elevated plasma VIIIR:WF levels in diabetics persist during overnigh sleep, but were not altered by wide swings in GH levels; (2) short-term careful diabetic control with insulin lowered plasma VIIIR:WF levels towards normal in the majority of subjects tested; and (3) increased sensitivity of platelets to aggregating agents appeared during tight insulin therapy in those subjects studied.

Decreased Platelet Vitamin C in Diabetes Mellitus; Possible Role in Peraggregatoon

To determine whether Vitamin C might relate to the increased platelet sensitivity in the diabetic, we have measured levels of platelet Vitamin C and studied the effects of Vitamin C on platelet aggregation. Ascorbic acid levels in washed platelets from diabetics were significantly lower than from normals (4s.2±3 μg/1010 platelets vs. 2s.s±2 μg/1010 platelets, p<.001). The effects of ascorbic acid on platelet aggregation in vitro were studied by adding ascorbic acid in buffered solution (pH 7.35) prior to-aggregating agents. Ascorbic acid in platelet-rich plasma consistently inhibited platelet aggregation with threshold concentrations of ADP, epinephrine, and collagen. With washed platelets, ascorbic acid inhibited arachidonic, acid-induced aggregation. When platelets were incubated at 37°C for 10 minutes with varying concentrations of ascorbic acid, rewashed, and aggregation with arachidonic acid tested, aggregation was inhibited in a linear dose-dependent fashion. Oral ingestion of ascorbic acid (2 gm/day) for seven days by normal non-smoking males produced a marked inhibition of aggregation. In a similar study, platelets from an insulin-dependent diabetic showed no change in aggregation. These results suggest that platelet levels of ascorbic acid may relate to the hyperaggregat ion of platelets from diabetics.

Prophylaxis of the laminectomy membrane. An experimental study in dogs

Sixty laminectomies were performed in dogs to investigate the prevention of the laminectomy membrane and its side effects. These operations were distributed in six groups of 10, one was a control group, and in the others the bone defect was protected with different materials (Oxicel, Silastic, Dacron, methyl methacrylate, and Kiel bone graft). After a survival of 2 months, suboccipital myelography was performed, immediately after which the animals were sacrificed and the operated spinal slice obtained. The different radiographic densities of the tissues of each slice were calculated and the diverse histological nature identified by hematoxylin and eosin, periodic acid Schiff, Masson's trichrome, and Gomori's reticulin strains. Only the acrylic plastic and the Kiel bone graft prevented expansion of the scar tissue inside the spinal canal and adhesions between the dura and the cicatrical overlying muscles. Therefore, the authors suggest that a solid barrier is necessary to effectively prevent the so-called "laminectomy membrane."

"Idiopathic" Bence-Jones proteinuria

During a prospective screening for proteinuria in diabetic patients, isolated Bence-Jones proteinuria was detected in 2 cases. The first patient, a 52-year-old black female, was seen for evaluation of a slow but progressive weight loss which was attributed to poor adjustment of insulin therapy. The patient gained weight after an increase of the daily insulin administration. She had plasmocytosis in a bone marrow aspirate, but no other evidence of myelomatosis. The second patient, a 59-year-old black male who was seen for routine evaluation of his diabetes, had no clinical or laboratory evidence of myelomatosis. Although precise definition of these cases as "benign" or "idiopathic" Bence-Jones proteinuria is impossible without prolonged follow-up, at the time of presentation they appeared to fit this classification. This observation is one further example that isolated Bence-Jones proteinuria may be seen without any evidence of malignant B-cell dyscrasia.

A lymphoproliferative disease in Japanese Quail

A naturally occurring lymphoproliferative disease was found in 3 flocks of Japanese quail in Mexico. The tumorlike lesions were detected mainly in livers and spleens. Histopathology revealed a pleomorphic lymphoproliferative infiltration with dark-staining large cells, lymphocytes of different sizes, and reticulumlike cells. Marek's disease (MD) herpesvirus was not isolated from 74 quail tested, nor were antibodies to MD detected in 84 sera. Antibodies to reticuloendotheliosis (3/24) and avain leukosis virus subgroup A (2/24) were present. The possible etiology of this disease is discussed.

An angiographic study of meningiomas of the posterior fossa

✓ The meningeal vasculature of the posterior cranial fossa was studied on injected normal anatomical specimens and in angiograms of patients with posterior fossa meningiomas. The correlated results indicate that the dura anterior to the foramen magnum is supplied by meningeal vessels from the carotid siphon, the ascending pharyngeal and middle meningeal arteries. The dura posterior to the foramen magnum is supplied primarily by the occipital artery and secondarily by the vertebral artery.