Capsular injuries of the proximal interphalangeal joint.

Although capsular injuries of the PIP joints are common, their management is frequently complicated. Successful treatment must begin with a detailed history because reviewing the mechanism of injury may provide information relevant to the pathomechanics of the capsular disruption and facilitate making an accurate diagnosis. Grades I and II volar plate and collateral ligament sprains represent the vast majority of PIP joint injuries. They are best treated with a short period of dorsal splinting followed by supervised mobilization. Although splinting is also applicable for grade II sprains associated with instability and most grade III sprains, the initial period of immobilization should be longer. The prognosis for recovery is generally good, although some residual tenderness or joint stiffness are common complications. Dorsal capsular injuries, if unrecognized, result in deformity rather than instability. The majority of these injuries can also be treated by closed means, but they require more prolonged immobilization and more commonly result in reduced mobility than volar plate and collateral ligament injuries. Capsular injuries that are compound, irreducible, or associated with a large intraarticular fracture can result in serious problems. Frequently, these injuries require primary surgical treatment, particularly in the case of the irreducible dislocation, which always requires surgery. An exception to the generally poor prognosis of these injuries is the irreducible volar dislocation because the central tendon remains intact permitting early postoperative joint mobilization. A chronic dislocation or late instability are fortunately not common sequela of capsular injuries; however, when they do occur, surgery is required.     

A comprehensive eye/vision program

As an essential element of the comprehensive rehabilitation efforts at Northport VA Medical Center, and as a service whose demand is projected to increase substantially with the expanding proportion of aging veterans, eye/vision care has become increasingly important. As a result, the administration of the Medical Center decided to heed the suggestions of Congress and the Director of Optometry in VA Central Office and reorganize the delivery of eye/vision services so the ever-increasing demand could be met more rationally, efficiently and effectively. In this paper, the Northport VA Medical Center's Comprehensive Eye/Vision Program, including the residency program in rehabilitative optometry, will be described and the benefits of the reorganization will be discussed.     

Therapeutic insemination by donor (TDI) achieves high pregnancy rates in infertile couples regardless of male motile sperm density

Therapeutic insemination by donor (TDI) was just as successful in achieving pregnancies in couples in whom the male counterparts had subnormal motile densities as in those with normal levels. All wives in this study had an infertility factor that was corrected and remained so for at least 8 months. Thus, motile density may not be a particularly good predictor of male fertility potential.     

Multiple unit activity study of brain stem and limbic structures during environmental habituation and circadian rhythm

Multiple unit activity (MUA) of brain stem, hypothalamic and limbic structures was studied during habituation to a novel environment and circadian rhythm in chronically implanted freely moving rats. MUA was analysed in the mesencephalic reticular formation (MRF), area hypothalami posterior (PH), basal nuclear group of amygdala (AMY), area septalis (SEPT), dorsal hippocampus (HIPP) and area hypothalami anterior (AH). It was found that in the novel environment MUA of all subcortical structures increased to a high level. During habituation MUA in each phase of wakefulness--sleep cycle decreased to stable low level both in brain stem and forebrain structures. Gradual decrease in MUA was characteristic to MRF, and a sharp decrease occured in AH and AMY. The environmental habituation proved to be a long lasting process in rat. During all phases of wakefulness--sleep cycle activity was significantly higher in the light period than in the dark, and MUA base level showed circadian variation both in brainstem and limbic structures. Close correlation was found between the actual MUA level and responsiveness to various sensory modalities both during habituation and circadian rhythm. The higher the MUA level, the higher the responsiveness, and a fall in activity was accompanied by decreased neuronal responsiveness.     

ATP-sensitive K+ channels in the hypothalamus are essential for the maintenance of glucose homeostasis

Glucose-responsive (GR) neurons in the hypothalamus are thought to be critical in glucose homeostasis, but it is not known how they function in this context. Kir6.2 is the pore-forming subunit of K(ATP) channels in many cell types, including pancreatic beta-cells and heart. Here we show the complete absence of both functional ATP-sensitive K+ (K(ATP)) channels and glucose responsiveness in the neurons of the ventromedial hypothalamus (VMH) in Kir6.2-/- mice. Although pancreatic alpha-cells were functional in Kir6.2-/-, the mice exhibited a severe defect in glucagon secretion in response to systemic hypoglycemia. In addition, they showed a complete loss of glucagon secretion, together with reduced food intake in response to neuroglycopenia. Thus, our results demonstrate that KATP channels are important in glucose sensing in VMH GR neurons, and are essential for the maintenance of glucose homeostasis.     

Intrarenal oxygen tension measured by a modified Clark electrode at normal and low blood pressure and after injection of x-ray contrast media

 The oxygen tension (pO₂) in the rat kidney was studied using a Clark microelectrode with a guard cathode behind the sensing cathode. The mean (± SEM) outer tip diameter of the electrodes used was 5.5 ± 1.9 μm. The zero-pO₂ current amounted to 12.5 ± 0.9 pA at 37°C; at air saturation it was 252 ± 22.9 pA. Rats with a systolic blood pressure (BP) above 80 mmHg (where 1 mmHg = 133 Pa) showed an average pO₂ in the cortex of 45 ± 2 mmHg and in the outer medulla of 31 ±1 mmHg. In rats with a BP below 80 mmHg a paradoxically high outer medullary pO₂ of 40 ± 4 mmHg was found, while the pO₂ in the cortex was 27 ± 4 mmHg. Changes in pO₂ were also noted in the renal cortex and outer medulla after intravenous injections of the x-ray contrast medium diatrizoate (370 mg iodine/ml). In rats with normal BP, injection of diatrizoate caused a slight fall in pO₂ in the renal cortex, from 42 ± 4 to 38 ±4 mmHg. In the medulla pO₂ decreased significantly from 34 ± 6 to 20 ±4 mmHg. Ringer’s solution did not induce any changes. Received: 9 September 1996 / Received after revision: 22 May 1997 / Accepted: 23 May 1997     

The use of Teflon-embedded calcium sulphate: dysprosium thermoluminescent dosimeters for chest radiography

As part of a U.S. multi-regional pilot study conducted by the six Centers for Radiological Physics, 12-mm-diameter by 0.4-mm-thick CaSO4:Dy Teflon-embedded discs were evaluated and used to measure patient entrance exposure on 60 "average" patients at 12 clinical centers. The discs were found to have adequate sensitivity, reproducibility and linearity up to 69.7 microC kg-1 (270 mR). The minimum measurable exposure was estimated as 0.4 microC kg-1 (1.5 mR). All responses were corrected for energy dependence, which varied +/- 20% from 1.7 to 6.5 mm Al half-value layer. Patient entrance exposure values ranged from 1.3 to 28 microC kg-1 (5 to 110 mR), with a median value of 5.2 microC kg-1 (20 mR). This value agreed with exposure measurements made on the chest radiography equipment using an ionization chamber and a phantom which simulated an "average" patient, and with published Nationwide Evaluation of X-Ray Trends (NEXT) data for the same period.     

Preliminary report of mortality among workers compensated for work-related asthma

BACKGROUND: Although fatalities due to asthma have been reported among subjects with occupational asthma (OA) associated with re-exposure, groups of subjects with work-related asthma have not been systematically followed up for mortality. During a review of compensation claims for asthma in Ontario, we identified 3 respiratory deaths among subjects previously compensated for OA for whom their surviving spouses received death benefits. This suspected "cluster" prompted us to undertake an investigation to examine mortality pattern among workers compensated for work-related asthma. METHODS: Subjects receiving compensation for OA or aggravation of asthma (AA) between 1980 and 1993, and a comparison sample of workers with claims for musculoskeletal injuries during the same period were identified from the Ontario Workers' Compensation Board. We also identified another comparison group of non-compensated asthmatic patients seen at a hospital clinic during the same period. The files of those with work-related asthma were reviewed to determine if OA or AA was adequately documented. Mortality was ascertained by linkage with the Mortality Database at the Ontario Cancer Registry through 1996. We compared the mortality of the three groups with that expected in the general population of Ontario using SMRs, and directly by proportional-hazards regression. RESULTS: The study included 3,070 subjects: 1,112 with work-related OA/AA with adequate documentation, 1,556 with work-related injuries, and 402 patients with non-work-related asthma. Of the 66 deaths identified, only 2 deaths were due to asthma, both in the work-related asthma group: one from the index cluster and one not previously identified. A second index death was coded as dying from COPD not elsewhere classified (ICD9 496), while the third index death also died of asthma but there was not sufficient information documenting OA to include the subject in the analyses. As compared with the general population, there were fewer deaths than expected from most causes, except for deaths among the work-related asthma claimants and the nonwork-related asthma patients from respiratory diseases (SMRs 1.3 and 5.9, respectively; 0.5 among injury claimants), all chronic obstructive lung disease (ICD9 490-496; SMRs 2.3 and 7.7, respectively), and asthma (SMRs 18.2 and 0, respectively). In direct comparison of the work-related asthma claimants with the injury claimants, the risk of death appeared elevated from respiratory disease (RR 2.6) and ischemic heart disease (IHD) (RR 2.8) but the confidence intervals included unity. CONCLUSIONS: This preliminary report raises the possibility that serious outcomes, including excess deaths from respiratory disease, in particular asthma, may occur among those with work-related asthma even in the absence of re-exposure. However, the findings are inconclusive given that the number of deaths was small and we identified only one new asthma death in addition to the index cluster. We also observed for the first time that deaths due to circulatory disease, particularly IHD, may also be increased among such workers; this needs to be confirmed elsewhere.     

Chronically decreased oxygen tension in rat pancreatic islets transplanted under the kidney capsule

BACKGROUND: A factor of potential importance in the failure of islet grafts is poor or inadequate engraftment of the islets in the implantation organ. This study measured the oxygen tension and blood perfusion in 1-, 2-, and 9-month-old islet grafts. METHODS: The partial pressure of oxygen was measured in pancreatic islets transplanted beneath the renal capsule of diabetic and nondiabetic recipient rats with a modified Clark electrode (outer tip diameter 2-6 microm). The size of the graft (250 islets) was by purpose not large enough to cure the diabetic recipients. The oxygen tension in islets within the pancreas was also recorded. Blood perfusion was measured with the laser-Doppler technique. RESULTS: Within native pancreatic islets, the partial pressure of oxygen was approximately 40 mm Hg (n=8). In islets transplanted to nondiabetic animals, the oxygen tension was approximately 6-7 mm Hg 1, 2, and 9 months posttransplantation. No differences could be seen between the different time points after transplantation. In the diabetic recipients, an even more pronounced decrease in graft tissue oxygen tension was recorded. The mean oxygen tension in the superficial renal cortex surrounding the implanted islets was similar in all groups (approximately 15 mm Hg). Intravenous administration of glucose (0.1 gxkg(-1)x min(-1)) did not affect the oxygen tension in any of the investigated tissues. The islet graft blood flow was similar in all groups, measuring approximately 50% of the blood flow in the kidney cortex. CONCLUSION: The oxygen tension in islets implanted beneath the kidney capsule is markedly lower than in native islets up to 9 months after transplantation. Moreover, persistent hyperglycemia in the recipient causes an even further decrease in graft oxygen tension, despite similar blood perfusion. To what extent this may contribute to islet graft failure remains to be determined.