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Biomedical subjects

L G Martin

Publications and source records attributed to L G Martin.

At least 55 records · Page 3Linked to original sources
PubMed1992

Different roles for two enhancer domains in the organ- and age-specific pattern of polyomavirus replication in the mouse.

Viral replication in mice infected with murine polyomavirus strains with novel enhancer rearrangements was analyzed by direct in situ hybridization of whole mouse sections and by hybridization of nucleic acids extracted from a specific set of organs. The enhancer rearrangements included a deletion of the B domain as well as duplications within the A domain. Comparisons between enhancer variants demonstrate that the B domain plays an important role in replication in most organs, in particular in the kidney, at the neonatal stage (days 0 to 7 postbirth). In contrast, the B domain is not required in those organs which can sustain replication in the adult, i.e. mammary gland, skin, and bone (class I organs [J. J. Wirth, A. Amalfitano, R. Gross, M. B. A. Oldstone, and M. M. Fluck, J. Virol. 66:3278-3286, 1992]). Altogether, the results suggest that the B and A domains mediate very different functions in infection of mice, controlling the acute and persistent phases of infection, respectively. A model of mouse infection based on the crucial role of differentially expressed host transcription factors is presented.

Aging↗
PubMed1992

Arterial injuries associated with complete dislocation of the knee.

To determine the frequency and type of arterial injuries associated with complete dislocation of the knee and to correlate the findings at physical examination with those at arteriography, a computerized search for patients with a diagnosis of dislocation of the knee at discharge from an urban trauma hospital was performed. Nineteen patients with complete dislocation of the knee were found. Arterial injuries were seen in six patients (32%). Four of the 19 patients had no pedal pulse at physical examination. In three of these four patients, occlusion of the popliteal artery was seen on arteriograms. The fourth patient had occlusion of an anomalous anterior tibial artery and a compartmental syndrome. Two of the 15 other patients with pedal pulses (13%) had nonoccluding intimal defects of the popliteal artery; these two patients did well without surgery. It is concluded that abnormal peripheral pulses associated with complete knee dislocation are highly predictive of major arterial injury. If peripheral pulses are normal, a low but definite frequency of arterial damage exists.

Adult↗
PubMed1992

Peripheral transcatheter embolization with platinum microcoils.

Embolotherapy with platinum microcoils delivered through the Tracker-18 microcatheter (Target Therapeutics, San Jose, Calif) was performed in 16 patients when peripheral superselective catheterization with standard angiographic catheters was not possible. The Tracker-18 catheter could be directed distally into small peripheral vessels for delivery of the microcoils. These microcoils, with attached fiber strands, resulted in vascular occlusion within a few minutes in all cases. Embolotherapy was technically successful in all patients. The procedures were clinically successful in 15 of 16 patients (94%), and no complications were encountered. Embolization with platinum microcoils through the Tracker-18 catheter is useful when standard methods of embolization are not possible.

Adolescent↗
PubMed1992

Japan's Golden Plan for the elderly.

One of the most industrialized nations in the world, Japan has an increasing number of workers reaching retirement age. Faced with tremendous health care costs for its elderly, Japan has proposed a 10-year plan to lessen costs and put health care back into the community.

Aged↗
PubMed1991

Population aging policies in East Asia and the United States.

As a result of successful efforts to reduce fertility and mortality, East Asian populations are beginning to age, in some cases rapidly. Policies in response to population aging range from attempts in Singapore to reverse it by encouraging more births to efforts in Japan to accommodate it by increasing employment opportunities for older workers. The population of the United States, which had a longer postwar baby boom, is aging more slowly than these two countries and may be able to learn from the East Asian experience with aging policies.

Aging↗
PubMed1991

Therapy of the Kasabach-Merritt syndrome with cryoprecipitate plus intra-arterial thrombin and aminocaproic acid.

A patient with the Kasabach-Merritt syndrome with disseminated intravascular coagulopathy and congestive heart failure due to a giant hepatic cavernous hemangioma achieved thrombosis of his tumor with a combination of cryoprecipitate plus intra-arterial thrombin and epsilon aminocaproic acid. This was documented by an absence of Indium 111-labelled platelet sequestration, marked decrease in thrombin:antithrombin complex generation, and normalization of platelet count and fibrinogen. Interventional angiography with aminocaproic acid and thrombin is advocated in patients whose tumors are amenable to such an approach so as to avoid a systemic antifibrinolytic state.

Aged↗
PubMed1991

Young Investigator Award. Raman spectroscopy of human atherosclerotic plaque: implications for laser angioplasty.

Raman spectroscopy is a specialized technique that permits highly specific identification of specimens, in contrast to fluorescence spectroscopy with which analysis of arterial tissues generates spectra that are broad and featureless, with little difference seen between normal artery and atheroma. Various plaque types and the contributions of different arterial fluorophores were studied to determine if Raman spectroscopy could function as a potential guidance modality for laser angioplasty. Arterial specimens obtained at atherectomy and post mortem were studied in air and while immersed in blood. One hundred fifty-six Raman spectra were collected from arterial specimens and chromatographic samples of collagen, elastin, cholesterol, beta-carotene, and L-tryptophan. Analysis showed both fatty and fibrous atherosclerotic plaques to have characteristic spectral peaks at 1,002, 1,154, and 1,516 cm-1, while the Raman spectrum of normal vessel was featureless. Spectral peaks of beta-carotene were nearly identical to those of fatty plaque. The arterial fluorophores collagen, elastin, cholesterol, and L-tryptophan were non-contributory. The Raman spectrum of fatty plaque immersed in a blood field was also detectable, suggesting that this technique may be useful for in vivo plaque recognition.

Angioplasty, Laser↗
PubMed1991

The utility of 99mTc-mercaptoacetyltriglycine in captopril renography.

99mTc-Mercaptoacetyltriglycine (MAG3) is a new 99mTc renal radiopharmaceutical with properties similar to orthoiodohippurate (OIH). 99mTc-MAG3 is highly protein bound and is efficiently extracted by the proximal tubules. While the clearance is only 50 to 65% that of OIH, the plasma concentration is higher and the rates at which the two tracers appear in the urine are almost identical. Studies comparing 99mTc-MAG3 and OIH in animals with renovascular hypertension (RVH) show comparable results. Preliminary studies comparing 99mTc-MAG3 renography with angiography in hypertensive patients show promising results and suggest 99mTc-MAG3 will probably have a sensitivity and specificity for detecting RVH similar to OIH. The optimal criteria for defining an abnormal study still need to be determined and then applied in a prospective study.

Animals↗
PubMed1991

Benign biliary strictures: treatment with percutaneous cholangioplasty.

Results of percutaneous balloon cholangioplasty of 17 patients with 28 benign biliary strictures were compared with those of published radiologic and surgical series to determine whether stricture location was related to therapeutic success and whether a patient should undergo percutaneous or surgical therapy. Treatment was considered successful if there was no anatomic evidence of recurrent stricture or need for surgery (mean follow-up, 32 months). Treatment was successful in all nine (100%) intrahepatic (zone 1) strictures, 11 of 12 (92%) extrahepatic-extrapancreatic (zone 2) strictures, one of three (33%) intrapancreatic (zone 3) strictures, and three of four (75%) bilienteric anastomotic (zone 4) strictures. Restenosis occurred in five patients; cholangioplasty was ultimately successful in two of those patients after redilation and stent placement. On the basis of these results and those of published radiologic and surgical series, the authors believe that cholangioplasty is the treatment of choice for zone 1 strictures and is as effective as surgery for zone 2 and 4 strictures. Patients with zone 2 and 4 strictures with concomitant portal hypertension or a history of multiple previous biliary surgical procedures should be considered good candidates for cholangioplasty. Zone 3 strictures may be better treated surgically than percutaneously.

Aged↗
PubMed1990

Identification and sequence analysis of four complement factor H-related transcripts in mouse liver.

Mouse liver RNA analyzed by Northern blotting with a full-length complement factor H cDNA probe demonstrates the 4.4-kilobase (kb) H mRNA as well as three additional hybridizing species of 3.5, 2.8, and 1.8 kb, respectively. Further characterization of these alternative transcripts was pursued by isolation of additional cDNAs from a liver library using a full-length H probe. Twelve clones homologous to but distinct from H were isolated, analyzed by restriction mapping, and divided into four classes, A, B, C, and D, based on their sequences. Clones from classes A, B, and C all contained nearly identical 5'-untranslated regions and leader sequences that differed from H at more than 50% of their nucleotide positions. The 5'-untranslated and leader sequences of the class D clone were unrelated to the corresponding regions of H or the class A, B, or C clones. The remaining portions of the H-related cDNAs were made up of short consensus repeats, 7 in class A, 4 in class B, 13 in class C, and 5 in class D. To determine the relationship between the H-related transcripts and the cDNA clones, Northern blots of liver RNA were analyzed by hybridization with two probes, one specific for the class D cDNA and the other reacting specifically with the class A, B, and C cDNAs. The class A/B/C probe detected transcripts of 3.5, 2.8, and 1.8 kb in liver RNA, and the class D probe hybridized to a distinct 1.8-kb message. Additionally, a cosmid genomic library was screened with H cDNA, and nine H-related clones were isolated. They spanned a region of approximately 120 kb, defining at least two discrete H-related gene loci. These results identify new members of the super-family of C3b/C4b binding protein genes.

Amino Acid Sequence↗
PubMed1990

A simplified radioenzymatic method for the study of whole blood histamine release in patients receiving radiographic contrast media.

With the availability of a newly developed, histamine-dependent allergy blood test, the authors studied the effect of ionic and nonionic radiocontrast media (RCM) on the in vitro release of histamine from whole blood obtained from 61 patients undergoing diagnostic arteriography. The ionic RCM, sodium meglumine diatrizoate (60 to 378 mmol/L), induced the release of a significantly (P less than .005) higher amount of histamine from blood compared with the nonionic agents, iopamidol and ioversol. Diatrizoate triggered significantly (P less than .05) more histamine release from the blood of eight patients with a history of adverse reactions to RCM than it did in 53 nonreactors; however, there was no appreciable difference in histamine release between reactive and nonreactive groups when stimulated with iopamidol and ioversol.

Contrast Media↗
PubMed1990

Angioplasty for long-term treatment of patients with Budd-Chiari syndrome.

The goal of radiologic intervention in patients with Budd-Chiari syndrome is to control portal hypertension and prevent further hepatocellular damage until collateral hepatic venous outflow channels can develop. Percutaneous balloon angioplasty was used to treat six patients with this syndrome who were followed up for an average of 43 months (range, 12-92 months). Standard interventional radiologic techniques were used to dilate the hepatic veins (two patients), inferior vena cava (three patients), and proximal anastomosis of a mesoatrial shunt (one patient). Angioplasty was the only invasive treatment in three patients, whereas the remaining three patients had previous portosystemic shunts. Clinical and hemodynamic improvement occurred after each angioplasty. Multiple dilatations were required in all patients (average, 3.2; range, 2-5) because of restenosis at the angioplasty site and ongoing hepatocyte necrosis shown by biopsy. Long-term benefit occurred in five patients despite ultimate caval occlusion in two patients and restenosis in one patient. One patient who was almost free of symptoms for 36 months developed gastrointestinal bleeding caused by portal hypertension. This experience suggests that balloon angioplasty is a safe and effective treatment for patients with Budd-Chiari syndrome. The therapy is not definitive, but serves to moderate the severity of the disease until collateral venous pathways develop. Multiple angioplasties are required for the long-term care of these patients.

Adult↗
PubMed1989

The graying of Japan.

Japan's rapidly aging population has become a top policy issue, especially as the increasing costs of pensions and medical care are debated. With the highest life expectancy on earth, the Japanese potentially face long periods of retirement, as well as the possibility of long periods of disability. Although family support of the elderly is thought to have been strong traditionally, the recent decline in co-residence with children is 1 indication that the way support is given may be changing. This issue is of particular concern to the government, which wants to avoid any greater responsibility for the elderly than is necessary given the dramatic population aging yet to come. The government is also encouraging employers to provide more employment opportunities for the elderly at the same time that it is trying to raise the eligibility age for the receipt of public pensions. There is resistance on the part of employers, however, because wages and retirement allowances in Japan are positively related to length of employment. Furthermore, it is not clear whether elderly Japanese of the future will be as willing to work, if they learn to enjoy increased leisure early in their careers. Nevertheless, it is unlikely that population aging will lead to Japan's economic decline. Although the savings rate may decline somewhat, restructuring of the economy and continued overseas investment should keep the economy growing in the long run. Important in both the care of the frail elderly and the continued growth of the economy will be the roles played by middle-aged Japanese women.

Adult↗
PubMed1989

Living arrangements of the elderly in Fiji, Korea, Malaysia, and the Philippines.

Using logit techniques and data from surveys of the elderly conducted in 1984 under the auspices of the World Health Organization, this article investigates socioeconomic, cultural, and demographic determinants of living arrangements of the elderly. Having a spouse or children with whom to live has important effects on living arrangements. The results provide only weak support, however, for hypotheses based on modernization theory and point to the need for detailed data on transitions in living arrangements and for information about the younger generation as well as the older generation, both of which are involved in deciding who lives with whom.

Aged↗
PubMed1988

The aging of Asia.

This article reviews some of the demographic characteristics of population aging and the elderly populations in 14 Asian countries: health and life expectancy; sex ratio, marital status, and living arrangements; and rural versus urban residence, labor force participation, retirement, and income. It also focuses on current programs for the elderly populations in Asia and discusses three general issues of importance in the development of aging policies: (a) to what extent should the West be used as a model; (b) what should be the role of the family versus the government in caring for elderly people who cannot care for themselves; and (c) should eligibility for programs be based on age or need?

Aged↗
PubMed1988

Azotemia caused by renal artery stenosis: treatment by percutaneous angioplasty.

Percutaneous angioplasty of the renal artery was performed in 79 patients who had stable or climbing serum creatinine levels greater than 1.7 mg/dl and hemodynamically significant stenosis of the renal artery. Patients who had nonrenal causes of azotemia, nephropathy caused by iodinated contrast material, or serum creatinine levels that were declining while the patients were receiving medical therapy before angioplasty were excluded from the study. Angioplasty resulted in a significant (greater than 20%) decline in the level of serum creatinine (average, 2.7 mg/dl before to 1.7 mg/dl after) in 43% of these patients during an average follow-up period of 16 months. A significant decrease in the level of serum creatinine was seen in 61% of patients with bilateral stenosis, 38% of patients with unilateral stenosis with absent contralateral renal blood flow, and 38% of patients with unilateral stenosis and normal contralateral renal blood flow. Recapture of lost nephron function was least successful in patients whose levels of serum creatinine were greater than 4.0 mg/dl (14%); this included one (11%) of nine patients who were already on hemodialysis. We conclude that angioplasty of the renal artery can play a major role in the treatment of patients who have mild azotemia and bilateral stenosis of the renal artery. It is less successful in treatment of patients who have severe azotemia and those who have unilateral disease.

Angioplasty, Balloon↗