Biomedical subjects
Publications and source records attributed to R M Worth.
Validation of diagnostic codes in a sample of Hawaii medical insurance claims in 1986 to 1987 revealed 96% accuracy in hospital claims, high enough to supply data for research purposes. In physician claims the accuracy was only 62%. Initiation of two feedback loops to physicians from the insurer in 1989 resulted in a marked improvement of diagnostic coding accuracy by 1992 to 1994.
Two different patterns of leprosy have occurred in Hawaii. First is the continuing influx of infected people among immigrants from several leprosy-endemic areas. The number of new cases among their descendents has tended to abate within one generation after arrival in Hawaii. The most recent example of this has occurred in Asians arriving since immigration laws were liberalized in 1965, followed by a rise of imported leprosy, peaking in 1970-1980, then falling. The second pattern was an explosive epidemic among native Hawaiians, rising to its peak in the 1890s, then slowly subsiding, and now approaching zero. It appears that official disease-control efforts (physical isolation and/or early multidrug treatment) cannot fully explain the ending of the epidemic in Hawaii, in spite of the continuing importation of M. leprae. It is suggested that the influence of changing socioeconomic factors (nutrition, crowding, genetics) has been of importance, particularly among the Hawaiians, who have undergone profound foreign influence (both positive and negative) during the 150-year history of this epidemic. The late Dr. Ma Haide was responsible for leprosy control in China, where leprosy is also fading away, but not simultaneously in all subpopulations. He summarized his view by saying, "Leprosy lingers longest among the poorest" (personal communication). This statement appears to hold true for Hawaii, also.
At the Indiana University Medical Center, 99 patients with medically intractable complex partial seizures (MI-CPS) had presurgical evaluation with subsequent anterior temporal lobectomy. The majority of the patients had single photon emission tomography (SPECT) performed interictally as well as during an actual epileptic seizure (ictal scan). Decreased regional cerebral perfusion (rCP) was seen in 54/94 (57%) of the interictal scans corresponding to the eventual site of the surgery. However, ictal scans provided a higher yield; increased rCP in the temporal lobe during an actual seizure was observed in 60/82 (73%) concordant to the side of surgery. SPECT is a useful, noninvasive method of localizing the epileptiform focus in patients with MI-CPS considered for resective surgery. Both interictal and ictal SPECT need to be performed; combined interictal hypoperfusion and ictal hyperperfusion in the same focal area are unique to epileptogenic lesions. Ictal SPECT studies can be performed in the majority of patients during the period of continuous video/EEG monitoring with only a little additional effort. Combining the results of functional brain imaging (interictal and ictal SPECT, PET) with clinical semiology of seizures, surface and sphenoidal EEG, magnetic resonance imaging and other non-invasive tests, anterior temporal lobectomy can be recommended in approximately two-thirds of the patients without resorting to potentially dangerous intracranial EEG monitoring.
Interictal and ictal HIPDM-SPECT brain scans were obtained in 38 patients who eventually underwent temporal lobectomy for treatment of medically intractable complex partial seizures (CPS). Interictal studies revealed decreased regional cerebral perfusion (rCP) in the temporal lobe corresponding to the eventual site of surgery in 76% of the patients. Similarly, ictal studies demonstrated increased rCP in 91% of the patients. Of the 33 patients who had both interictal and ictal SPECT studies, 23 (70%) showed increased rCP in the ictal state and decreased rCP in the interictal state in the same temporal lobe which was subsequently removed. The SPECT scans were particularly helpful in providing confirmatory evidence for localization and in deciding to undertake temporal lobectomy in 16 patients whose EEG studies had provided less secure localization. Our experience suggests that interictal and ictal SPECT brain imaging can be easily obtained and provides reliable localizing information in the epileptic patients being considered for temporal lobectomy.
The neurofibromatoses are two distinct entities with different genetic origins. The phenotypic expressions and required treatments are different. The devastating nature of neurofibromatosis-2 may be more effectively controlled through the application of advanced imaging techniques and contemporary neurotologic procedures. The most common manifestation of neurofibromatosis-2 is that of bilateral acoustic neuromas. The eventual total bilateral sensorineural deafness associated with this condition can be obviated in selected cases if the diagnosis is established early. Follow-up data are reported for three patients in whom hearing was preserved in at least one ear. When removal with hearing preservation is not possible, subtotal tumor removal with decompression of the internal auditory canals may delay progression of hearing loss. A new approach to tumors of the pterygomaxillary fossa that have extended to the middle cranial fossa has been successfully applied and is described.
Suprascapular nerve entrapment is an acquired neuropathy secondary to compression of the nerve in the bony suprascapular notch. A series of 27 cases, the largest reported to date, is presented and examined as to the best and most appropriate method of diagnosis and treatment. The entity is described in detail as to its origin, anatomy, and pathophysiology.
We report the results of interictal and ictal HIPDM-SPECT brain imaging in 34 patients who eventually underwent temporal lobectomy for treatment of medically intractable complex partial seizures. Interictal studies revealed decreased regional cerebral perfusion (rCP) in the temporal lobe corresponding to the eventual site of surgery in 73% of the patients. Similarly, ictal study demonstrated increased rCP in 93% of the patients. In 69% of the patients, the SPECT studies were able to demonstrate both increased rCP on the ictal scan and decreased rCP on the interictal scan in the same location, corresponding to the eventual site of surgery. These results suggest that interictal and ictal SPECT brain imaging can be easily obtained and provide reliable localizing information in the presurgical evaluation of patients with medically intractable epilepsy.
Twelve members of the Indiana hereditary amyloidosis type II kindred were tested for the presence of amyloid deposits. All were young adults (age 26-37), with no evidence of disease and with 1 affected parent. Six were found to be carriers of the variant gene, by DNA testing and/or reduced serum retinol-binding protein levels. Nevertheless, no amyloid could be found in any skin, rectal, or carpal tunnel biopsy specimens. Our results suggest that hereditary amyloidosis type II is a true late-onset disease, in which accumulation of amyloid does not start until late in life--perhaps only a short time before symptoms appear.
While there have been several cases of cerebral histoplasmoma published in the literature, the occurrence of such a lesion in an intramedullary spinal location has not previously been reported. The authors present a patient with a Brown-Séquard lesion secondary to an intramedullary Histoplasma granuloma in the cervical region. The case was successfully managed with surgical removal of the lesion.
Both interictal and ictal N,N,N'-trimethyl-N'-(2-hydroxy-3-methyl-5-iodobenzyl)-1,3,propanediamine -single photon emission computed tomography (HIPDM-SPECT) were performed in 16 patients with medically intractable complex partial seizures. Ictal HIPDM-SPECT localized epileptic foci in 13 of 14 patients with unilateral temporal focus and provided confirmative evidence of epileptic focus in 11 patients by demonstrating maximally increased regional cerebral perfusion (rCP) in epileptic foci that had shown decreased rCP in a previous interictal study. Ictal HIPDM-SPECT in two patients with bitemporal foci showed more complicated patterns consisting of slightly increased rCP in bilateral multifocal regions. Ictal HIPDM-SPECT was particularly useful for investigating epileptic foci, and correlation with simultaneously recorded ictal electroencephalograms provided further insight for localizing epileptic foci.
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HIPDM-SPECT brain imaging was performed in four patients with intractable complex partial seizures (CPS). Three patients had an epileptogenic focus in one temporal lobe and underwent anterior temporal lobectomy. Interictal HIPDM-SPECT demonstrated decreased regional cerebral perfusion (rCP) in the epileptogenic area in only one patient, but ictal studies showed increased rCP in the epileptic foci of all three patients. In the fourth patient, interictal HIPDM-SPECT showed increased rCP in the area of epileptogenic focus; when antiepileptic medication was taken, rCP decreased. HIPDM-SPECT brain imaging is useful for localizing epileptogenic foci in CPS.
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No standardized methods exist for reliably measuring physicians' performance against clinically valid standards. In this study, statistically reliable peer review based on current national standards of internal medicine was used to evaluate the clinical performance of 66 internists in office and hospital practice. Evaluation was limited to the substantiation of diagnosis, prescribing indicated drug regimen, monitoring, and attaining expected patient response. Performance in substantiating diagnosis was better than in therapeutic management, and management in hospitalized patients was superior to office management. Superior performance by a physician was not consistent across diagnoses, but substandard office treatment in at least one diagnosis was associated with substandard office treatment in other conditions. Internists' performance was unrelated to their certification status but inversely related to the number of years since graduation from medical school. This method could be used to evaluate the effectiveness of continuing education in improving physicians' performance and to validate current examinations used in recertifying internists.
Previous studies have detected circulating antibody in leprosy using a variety of difficult laboratory methods. We have developed a simpler method for detecting antibody by ELISA, using autoclaved Mycobacterium smegmatis as the antigen. Evaluation was performed on eluates from 25 microliter aliquots of finger-prick blood dried on filter-paper disks in two high-incidence populations in Ponape, Micronesia. Among 228 nonleprosy cases bled in 1980 and rebled and re-examined in 1982: a) for those who had been ELISA positive two years earlier, the leprosy attack rate during the intervening two years was at least twice as high as among those who had been negative, and we estimate that shortening the screening interval to one year plus doing confirmatory retests on new sero-converters would increase the relative risk (or "predictive power") to over sixfold, including all impending multibacillary cases; b) elevated antibody levels were detected up to two years prior to clinical onset of disease in 70% of new cases; and c) both asymptomatic conversion (rising titer) and reversion (falling titer) were observed. Among 150 biopsy-proven cases, ELISA results suggest that fall of titer in most uncomplicated paucibacillary cases was rapid (months), but in multibacillary cases was more gradual (years), probably paralleling responses to treatment with titers rising in reactivation. These results suggest that this technique, with an improved antigen, may be useful in leprosy control programs, both for detecting candidates for preventive treatment and for following responses to therapy.
Six patients representing seven cases of spontaneous (nontraumatic) saphenous neuralgia secondary to entrapment of the nerve in the subsartorial canal are presented. All patients complained of medial knee and leg pain. Clinical findings included tenderness over the subsartorial canal and sensory changes in the cutaneous distribution of one or both terminal branches of the saphenous nerve. The diagnosis was confirmed by saphenous nerve block in all cases. All patients were treated operatively, which resulted in symptomatic improvement. All six patients initially underwent external neurolysis; however, three patients required saphenous neurectomy for recurrent symptoms. Saphenous neuralgia should be considered in the differential diagnosis of medial lower extremity pain.
Batrachotoxin (BTX) in the low concentration range of 19-190 nM blocks axoplasmic transport in the desheathed cat peroneal nerve in vitro. When the level of Na+ in the incubation medium was reduced to 10 mM, the blocking effect of BTX was much diminished, and in an Na+-free medium BTX had no effect on transport at all. The blocking action of BTX with Na+ present was inhibited by increasing the concentration of Ca2+ in the experimental medium. Relatively small increases were effective with a maximum protection seen when the Ca2+ concentrations were 7-10 mM. The results support the view that an increase in axonal Na+ is inhibitory to the transport mechanism. The results are discussed on the basis of the recently developed transport filament model of axoplasmic transport which takes into account an obligatory role for Ca2+ in transport and its axonal regulation. The possible relation of intraaxonal Na+ concentration to the Ca2+ level is also discussed.