PubMed Health⌕ Search

Biomedical subjects

Akira Hebisawa

Publications and source records attributed to Akira Hebisawa.

At least 19 recordsLinked to original sources
PubMed2006

Telomere length, telomerase activity, and expressions of human telomerase mRNA component (hTERC) and human telomerase reverse transcriptase (hTERT) mRNA in pulmonary neuroendocrine tumors.

BACKGROUND: Telomeres are important for chromosome structure and function, protecting them against degradation. However, few studies have examined telomeres in pulmonary neuroendocrine (NE) tumors. METHODS: We investigated deparaffinized sections obtained from 70 primary NE lung tumors [34 typical carcinoids (TCs), 10 atypical carcinoids (ACs), 16 large cell neuroendocrine carcinoma (LCNECs) and 10 small cell lung carcinomas (SCLCs)]. RESULTS: Positive expressions of human telomerase mRNA component (hTERC) and human telomerase reverse transcriptase (hTERT) mRNA were recognized, respectively, in 58% and 74% of TCs, and in 100% and 100% of ACs, LCNECs and SCLCs. Alteration of telomere length was greater in both LCNECs and SCLCs than in TCs. Telomerase activity was detected in LCNECs, but not in TCs. By the reverse-transcriptase polymerase chain reaction (RT-PCR), hTERC mRNA was detected in 100% of LCNECs and TCs examined, while hTERT mRNA was detected in 67% of LCNECs, but not at all in TCs. CONCLUSIONS: These results suggest that alterations in telomere length, telomerase activity, and the expression of hTERT mRNA may (i) play roles in pathogenesis in pulmonary neuroendocrine tumors, and (ii) be a useful tool for differential diagnosis between TCs and LCNECs.

Carcinoma, Neuroendocrine↗
PubMed2006

Diagnostic value of thoracoscopic pleural biopsy for pleurisy under local anaesthesia.

BACKGROUND: We find pleural effusion in clinical practice frequently. However, it is difficult to make a diagnosis definitively by thoracocentesis or closed pleural biopsy. We directly examine the thoracic cavity by thoracoscopy under local anaesthesia, carry out pleural biopsy and make a definitive pathological diagnosis in pleurisy. METHOD: A retrospective study of 138 patients who had been diagnosed by thoracoscopy in our hospital was carried out between January 1995 and January 2005. RESULTS: The patients were 114 men and 24 women, ranging in age from 21 to 85 years, with a mean of 59 years. The right side was involved in 83 patients and the left side in 55. The operations took 11-145 min, with a mean of 46 min. Thoracoscopy directly without thoracocenteses was carried out in 28 of 138 patients. Lung cancer with pleural dissemination was diagnosed in 27, malignant pleural mesothelioma in 10, tuberculous pleurisy in 32, non-specific pleurisy in 58, other tumour in 2 and pyothorax in 9 patients. The overall diagnostic efficacy was 97.1% (134/138). The diagnostic efficacy in the cases of carcinoma was 92.6% (25/27), in malignant pleural mesothelioma it was 100% (10/10) and in tuberculosis it was 93.8% (30/32). No major complications occurred during the examination. CONCLUSION: Pleural biopsy by thoracoscopy under local anaesthesia should be actively carried out in patients with pleurisy, because the technique has a high diagnostic rate and can be easily and safely carried out.

Adult↗
PubMed2006

[Case of pulmonary mycobacterium avium complex disease, showing hypersensitivity pneumonitis-like diffuse shadow].

A 59-year-old man who had just completed therapy for tuberculosis, fell down in sauna and was admitted to a hospital. As acid-fast bacilli were positive (Gaffky 2) in sputum and residual cavity was shown in the right upper lobe on chest X-ray, he was transferred to our hospital. In spite of starting antituberculous chemotherapy, small nodular shadows appeared diffusely and were changed into ground-glass appearance on chest X-ray. The trans-bronchial-lung-biopsy revealed alveolitis mainly composed of lymphocyte infiltration with non-caseous epithelioid cell granulomas and organization which are likely to appear in hypersensitivity pneumonitis. As the acid-fast bacilli were identified as Mycobacterium avium, clarithromycin and kanamycin were added to the chemotherapy, but no improvement was observed in clinical feature. Corticosteroid therapy was further added and clinical feature improved immediately. Although we did not examine the presence of Mycobacterium avium in the water of sauna bath, we suspected this case as Hot Tub Lung based on clinical features and the response to treatment.

Alveolitis, Extrinsic Allergic↗
PubMed2006

[A case of pulmonary aspergillosis presenting the pulmonary arterial supply suggested with dynamic MRI].

A 67-year-old man with a past history of pulmonary tuberculosis had been referred to our department complaining of bloody sputum. The chest radiograph on admission showed a cavity in the left upper lung field. Chest CT showed a mass-like fungus ball in the cavity. Pulmonary aspergillosis was diagnosed from the sputum mycology, serum Aspergillus antigen and antibody. Even though 150 mg per day Funguard (micafungin sodium) was given intravenously for 4 weeks, the pulmonary aspergillosis did not improve. Dynamic MRI obtained 20 seconds after intravenous injection of contrast material revealed penetrating vessels in the wall of the cavity, and dilated and proliferative vessels surrounding the cavitary lesion. On the basis of the MRI findings which suggested the risk of massive hemoptysis, we performed left upper lobectomy. The histological specimen revealed dilated pulmonary arteries in the wall of the cavity, corresponding to the penetrating vessels on MRI. This is the first report of radiologic-pathologic correlation using dynamic MRI for pulmonary aspergillosis, to the best of our knowledge.

Aged↗
PubMed2006

Coexistent lung carcinoma and active pulmonary tuberculosis in the same lobe.

We observed a rare case of lung carcinoma accompanied by active pulmonary tuberculosis in the same lobe. The chest x-ray of a 49-year-old man revealed an abnormal shadow in the right upper field and a giant bulla in the left upper field. Chest computed tomography (CT) revealed a nodule with consolidation, which was not continuous in the right S3. Bronchoscopically, epidermoid carcinoma existed in the proximal right upper bronchus. In the sputum specimens, the smear was negative, but the polymerase chain reaction of Mycobacterium tuberculosis and culture was positive. Anti-tuberculosis treatments were administered for approximately 4 weeks, but the chest x-ray remained unchanged. Right upper lobectomy with bronchoplasty (wedge resection of the right upper bronchus) was performed, and the anastomosis was covered with an intercostal muscle flap. Lymphadenectomy of the right hilum and mediastum was also performed. Microscopy revealed epidermoid carcinoma in the proximal tumor (pT3N0M0-stage IIB) and epithelioid granuloma with caseous necrosis, granulomatous pneumonia, exudative lesions, and fibrocaseous nodules in the distal lung. After surgery, anti-tuberculosis treatment was resumed.

Antitubercular Agents↗
PubMed2006

[An autopsy case of obliterative bronchiolitis associated with Stevens-Johnson syndrome].

We reviewed an autopsied 27-year-old female with obliterative bronchiolitis associated with Stevens-Johnson syndrome. She had a history of Stevens-Johnson syndrome at age 10 years old and was treated with corticosteroids. Two months after the onset of dermatitis, the patient complained of dyspnea on exertion. The chest radiograph showed hyperinflation, and pulmonary function tests revealed obstructive impairment. The respiratory failure progressed due to respiratory tract infection and pneumothorax. She underwent thoracoscopic cyst surgery for right pneumothorax. Although the patient was clinically diagnosed as having obliterative bronchiolitis and received corticosteroids therapy and mechanical ventilation, she died of progressive respiratory failure 17 years after the onset of Stevens-Johnson syndrome. On autopsy, the macroscopic appearance of both lungs showed multiple white nodules in the centrilobular lesion corresponding to the obliteration of the small bronchioli. The microscopic appearance revealed constrictive bronchiolitis in the membranous bronchioli of both lungs associated with secondary bronchiectasis caused by superimposed infection.

Adult↗
PubMed2006

Thoracoscopic pleural biopsy for tuberculous pleurisy under local anesthesia.

OBJECTIVE: We directly examined the thoracic cavity by thoracoscopy under local anesthesia, performed pleural biopsy, and made a definitive pathological diagnosis in tuberculous pleurisy. SUBJECTS AND METHODS: We performed a retrospective study of 32 patients who had been bacteriologically and pathologically diagnosed with tuberculous pleurisy by thoracoscopy under local anesthesia in our hospital between January 1995 and November 2004. RESULTS: Bacteriological examination of pleural fluids obtained by thoracentesis before examination showed that one sample was polymerase chain reaction (PCR)-positive, and 5 samples were culture-positive. Bacteriological examination of pleural fluids obtained by thoracoscopy revealed that 2 samples were PCR-positive, and 5 samples culture-positive, including 2 preoperatively positive samples. The adenosine deaminase (ADA) levels ranged from 18.3 to 279.0 U/L, with a mean of 72.9 U/L, including 50 U/L or less in 5 patients and 35 U/L or less in 3 patients. Thirty patients (93.8%) were successfully diagnosed by pleural biopsy with pathological examination, and 21 (65.6%) of them by pathological examination alone. CONCLUSION: In patients with suspected tuberculous pleurisy, thoracoscopic pleural biopsy under local anesthesia should be actively performed, because the technique has a high diagnostic rate, and can be easily and safely performed.

Adenosine Deaminase↗
PubMed2005

Comparative clinicopathology of obliterative bronchiolitis and diffuse panbronchiolitis.

BACKGROUND: The progressive airway obliteration caused by obliterative bronchiolitis (OB) has been widely noted in the world. In contrast, the obstructive respiratory disorder caused by diffuse panbronchiolitis (DPB) has been reported mainly from Japan. Therefore, there might be a considerable overlap between OB and DPB in Japan. OBJECTIVES AND METHODS: To clarify the clinicopathological similarities as well as the differences between OB and DPB, 15 patients with OB and 6 patients with DPB were evaluated clinicopathologically. RESULTS: The underlying disorders in OB were graft-versus-host disease (GVHD) in 7, rheumatoid arthritis in 3, Kartagener's syndrome in 2, and polymyositis/dermatomyositis, non-tuberculous mycobacterial disease and mycoplasmal pneumonia in one each. The lung pathology demonstrated that the primary obstructive lesions were in the membranous bronchioli in OB. In contrast, they were confined to the respiratory bronchioli in DPB. In addition, OB was classified into two major morphologic types, namely, constrictive and cellular. Clinical manifestations included cough and/or dyspnea in 13 with OB and in 6 with DPB, chronic parasinusitis in 3 with cellular OB and in 6 with DPB. The pulmonary function tests revealed obstructive impairments in all patients with OB and DPB. The chest CT images showed small centrilobular nodules in 64% of those with OB and in all with DPB. The prognosis of constrictive OB was worse than that of cellular OB and DPB. CONCLUSIONS: This study demonstrated that histopathologically marked differences existed between OB and DPB, although striking similarities in clinical manifestations were also noted in both diseases.

Adult↗
PubMed2005

Lymphangiogenesis-mediated shedding of LAM cell clusters as a mechanism for dissemination in lymphangioleiomyomatosis.

Lymphangioleiomyomatosis (LAM) affects exclusively women of reproductive age, involves the lungs and axial lymphatic system, and is frequently complicated with renal angiomyolipomas. LAM lesions are generated by the proliferation of LAM cells with mutations of one of the tuberous sclerosis complex (TSC) genes. Recent studies indicate that LAM cells can migrate or metastasize to form new lesions in multiple organs, although they show a morphologically benign appearance. In the previous study, we reported LAM-associated lymphangiogenesis and implicated its role in the progression of LAM. In this study, we further focused on the lymphatic abnormalities in LAM: LAM-associated chylous fluid (5 pleural effusion and 2 ascites), surgically resected diaphragm (1 patient), and axial lymphatic system including the thoracic duct, lymph nodes at various regions, and diaphragmatic lymphatic system (5 autopsy cases). We demonstrated that LAM cell clusters enveloped by lymphatic endothelial cells (LCC) in all chylous fluid examined. We identified LAM lesion in the diaphragm (2 of 5 autopy cases and one surgical specimen), thoracic duct (5 of 5), and lymph nodes (retroperitoneal (5 of 5), mediastinal (4 of 5), left venous angle (5 of 5) with total positive rate of 68% to 88% at each region of the lymph node, but less frequent or none at remote lymph nodes located away from the axial lymph trunk (cervical [1 of 5] and axillary [0 of 5]). LCCs were identified in intra-LAM lesional lymphatic channels where LAM cells proliferate along lymphatic system. In in vitro culture system, LCC can fragment into each proliferating LAM cell. These findings suggest that LAM-associated lymphangiogenesis demarcates LAM lesion into bundle- or fascicle-like structure and eventually shed LCC into the lymphatic circulation and that LCCs play a central role in the dissemination of LAM lesion.

Adult↗
PubMed2005

A case of invasive thymoma with endobronchial growth.

We report a rare case of invasive thymoma with endobronchial growth in a 69- year-old woman. Chest CT revealed an ill-defined mass with a calcified lesion in the anterior mediastinum and coin lesion in the bilateral lung fields. An endobronchial polypoid tumor in the right B3 bronchus was found by bronchoscopic examination. A biopsy specimen obtained from the polypoid tumor suggested thymoma. After radiotherapy combined with chemotherapy, thymothymectomy combined with right upper lobectomy through median sternotomy was performed. The surgical specimen revealed that the tumor extended nodularly, not only into the pulmonary parenchyma but also into the bronchial lumen. We performed an added chemotherapy for lung metastasis, and partial resection of lung with video-assisted thoracoscopic surgery (VATS) was done. Now she is alive and disease-free.

Aged↗
PubMed2005

[A case of malignant mesothelioma showing rapid progression during one month].

A 57-year-old man with massive right pleural effusion was admitted to our hospital. Thoracoscopy revealed, fine granulations and small nodules scattered on the parietal pleura. Biopsy specimens suggested malignant mesothelioma. We performed thoracoscopy again one month later under general anesthesia to make a definitive diagnosis. At that time, the parietal pleura was covered with a large tumor and malignant mesothelioma was diagnosed by biopsy. We could find early pleural lesions of malignant mesothelioma in thoracoscopy. While we managed to make a definitive diagnosis, the tumor progressed rapidly during one month. If malignant pleural mesothelioma is suspected, it is necessary to make all efforts, including surgical biopsy, to diagnose during the early stage of disease.

Biopsy↗
PubMed2005

[Coexistence of lung cancer and active pulmonary mycobacteriosis].

OBJECTIVES: The aim of this study is to clarify the clinical and pathological anatomical picture of cases in which lung cancer and active pulmonary mycobacteriosis are intermingled in the same lobe of the lung. MATERIALS AND METHODS: We analyzed clinicopathological data on 11 cases in which lung cancer and active pulmonary mycobacteriosis are intermingled in the same lung lobe out of 61 admitted cases of coexisting lung cancer and active pulmonary mycobacteriosis, encountered at National Hospital Organization Tokyo National Hospital during the period from 1991 to 2003. RESULTS: The subjects were 10 men and 1 woman, with a mean age of 68 years. The species of mycobacteriosis were M. tuberculosis in 6 and nontuberculous mycobacteriosis in 5 (M. avium disease and M. abscessus disease in 2 each, and M. kansasii disease in 1). The frequency of the mixture was 13% (6/45) in patients with lung cancer and tuberculosis and was 31% (5/16) in patients with lung cancer and nontuberculous mycobacteriosis. Radiographic findings revealed that both cancer shadows and mycobacteriosis shadows are identified in 8 of the 11 patients, whereas cancer shadows were recognized but mycobacteriosis shadows could not be pointed out in the remaining 3 patients. We divided 7 cases (5 resection scases and 2 autopsy cases) with the mixture of cancer and mycobacteriosis into 2 types from the macroscopic images: (1) type A (4 cases, the foci of lung cancer and tuberculosis, which were separated originally, progressed mutually, and has adjoined), and (2) type B (2 cases, the foci of mycobacteriosis existed within or in the edge of the foci of lung cancer). There were 3 nontuberculous mycobacteriosis cases and 1 tuberculosis case in type A, and 2 tuberculosis cases and 1 nontuberculous mycobacteriosis in type B. In nontuberculous mycobacteriosis cases, cancer and mycobacteriosis had often adjoined under the conditions of preexisting lung disease, such as a lung cyst, whereas in tuberculosis cases, it was characteristically shown that the wall of encapsulated caseous nodules was destroyed by cancer invasion, and that the tuberculous nodules were reactivated. These findings seemed to be related to exogenous infection of nontuberculous mycobacteriosis to the injured lungs and to endogenous reactivation of tuberculosis from inactive tuberculous lesions. CONCLUSION: Lung cancer and active pulmonary mycobacteriosis are often seen intermingled in the same lung lobe, and the mixture pictures of the two diseases are variable. The physicians should carefully note about the mixture of lung cancer and mycobacteriosis, though the findings are not clear on the chest plain radiographs.

Adult↗
PubMed2004

Chronic hypersensitivity pneumonitis caused by Aspergillus complicated with pulmonary aspergilloma.

A 57-year-old man consulted our hospital with a history of the gradual onset of dyspnea and a productive cough. Chest computed tomographic (CT) scans showed a nodular shadow in a cavity lesion, and reticulonodular, cystic, and ground-grass opacities in the bilateral lung fields with honeycombing. He was diagnosed as having pulmonary aspergilloma and idiopathic pulmonary fibrosis (IPF). As an outpatient, he suffered from dyspnea upon physical exertion with exacerbation of the high-resolution CT (HRCT) opacities. An inhalation provocation test for Aspergillosis fumigatus was positive and chronic hypersensitivity pneumonitis (CHP) caused by Aspergillus was finally diagnosed. Insidious CHP is sometimes misdiagnosed as IPF. The diagnosis of insidious CHP should be made on the basis of a detailed history, specific HRCT findings, and lymphocyte-dominant bronchoalveolar lavage fluid cell findings.

Alveolitis, Extrinsic Allergic↗
PubMed2004

[Thoracic malignancies in patients with chronic tuberculous empyema].

OBJECTIVES: To clarify features of thoracic malignancies occurred in patients with chronic tuberculous empyema. MATERIALS AND METHODS: We analyzed clinicopathological data of 15 patients with thoracic malignancies who had chronic tuberculous empyema, encountered at Tokyo National Hospital during the period from 1977 to 2002. RESULTS: There were 13 men and 2 women, with a mean age of 67 years. Most of all (13/15) patients had history of surgery for tuberculosis including artificial pneumothorax (9 cases). Malignancies consisted of pyothorax-associated lymphoma (PAL; 9 cases), lung cancer (4 cases), malignant fibrous histiocytoma (1 case), and angiosarcoma (1 case). There were no differences in background factors between PAL patients and the other patients. Common symptoms were chest pain (10 cases), fever (7 cases), and bloody sputum (4 cases) and it seemed that these symptoms were more evident in patients with PAL than in patients with other diseases. Plain chest X-ray films often failed to detect the tumor, and the diagnosis was often obtained by sputum cytology, bronchofiberscopy, transcutaneous biopsy, and resection with support of CT and/or MRI films. On radiographs, all tumors located in empyema cavities or around empyema walls, and a pulmonary mass adjacent to the empyema wall was characteristic of lung cancer. PAL showed certainly good outcome; 40% 5-year survival rate with resection or chemoradiotherapy. On the other hand, all of lung cancer cases were diagnosed at stage III, and had poor outcome, and the remaining patients with the other malignancies also had poor outcome. CONCLUSION: Clinicians should keep in mind occurrence of several thoracic malignancies during the follow-up of patients with chronic tuberculous empyema.

Aged↗
PubMed2004

[Pulmonary nontuberculous mycobacteriosis in patients with lung cancer].

OBJECTIVES: To clarify the clinical features of the coexisting lung cancer and nontuberculous mycobacteriosis of the lung. MATERIALS AND METHODS: We analyzed clinical data on 11 admitted cases of coexisting lung cancer and pulmonary non-tuberculous mycobacteriosis at National Organization Tokyo Hospital during the period from 1997 to 2002. RESULTS: There were 10 men and 1 woman, with a mean age of 66 years. Five of 11 patients had underlying pulmonary disorders, such as healed tuberculosis and lung cyst. Histological types of lung cancer were squamous cell carcinoma in 4, adenocarcinoma and small cell carcinoma in 3 each, and 8 out of 11 cases were in stages III to IV. We classified the 11 cases into 2 groups: (1) lung cancer concurrently detected with mycobacteriosis (8 cases) and (2) lung cancer sequentially detected during the follow-up of mycobacteriosis (3 cases). Lung cancers in the latter group were in relatively early stages and all patients of this group received resection of the cancer, while most of lung cancers in the concurrent group were in far-advanced, and palliative and/or supportive treatment for lung cancer were frequently selected. The strains of mycobacteria were as follows: M. avium complex (6 cases) and M. kansasii (5 cases). The incidence of lung cancer among patients with nontuberculous mycobacteriosis was 2.5 percent (2 percent of M. avium complex diseases patients and 8.2 percent of M. kansasii disease patients), while the incidence of nontuberculous mycobacteriosis in untreated lung cancer patients was 1.4 percent. Analysis of anatomical relationship between lung cancer and non-tuberculous mycobacteriosis revealed that the two diseases located in the same lung in 8 cases, and also in the same lobe in 4 out of the 8 cases. Outcome of treatment for nontuberculous mycobacteriosis was good especially in patients with M. kansasii disease, and it seemed that coexisting nontuberculous mycobacteriosis did not influence on the prognosis of lung cancer patients. CONCLUSION: In the management of lung cancer, physicians should consider the possibility of coexisting pulmonary non-tuberculous mycobacteriosis, as well as coexisting pulmonary tuberculosis.

Adult↗
PubMed2004

[A case of pulmonary aspergillosis with bone invasion and destruction in an AIDS patient].

A 59-year-old HIV-infected man who had been treated for pulmonary cryptococcosis in another hospital was suffering from pulmonary tuberculosis. He was admitted to our hospital for treatment of tuberculosis. The chest radiograph on admission showed a large cavity in the left lower lung field. Chest CT showed a mass like a fungus ball in the cavity. Pulmonary aspergillosis was diagnosed from the sputum mycology and serum immunoprecipitins. During the treatment of pulmonary tuberculosis and cryptococcosis, thickening of the wall of the cavity was seen together with adjacent bone destruction. In an autopsy, Aspergillus spp. Were found to have invaded the bone tissue and caused bone destruction. Pulmonary aspergillosis in an AIDS patient is infrequent, and is rare in additional association with bone invasion and destruction.

Acquired Immunodeficiency Syndrome↗
PubMed2004

[Molecular pathogenesis in tuberculosis complicated with AIDS].

HIV-1 infection is a major cause of worldwide epidemic of tuberculosis. There is increasing clinical evidence that coinfection with M. tuberculosis accelerates progression of AIDS. We found that, in vivo, HIV-1 load and mutation increase in involved lung segments in patients with pulmonary tuberculosis. We also reported that Mycobacterium tuberculosis stimulates HIV-1 replication by enhancing transcription on the 5' LTR in a macrophage cell line, THP-1, in vitro. In contrast, HIV-1 replication is suppressed by M. tuberculosis infection of monocytes derived macrophages (MDM) or differentiated monocytic THP-1 cells. We observed that HIV-1 5' LTR function was repressed in PMA differentiated THP-1 cells after co-infection with M. tuberculosis. Point mutations in C/EBP beta binding domains of the HIV-1 LTR negative regulatory element (NRE) abolished promoter repression. Monocyte-derived macrophages and differentiated THP-1 cells increased expression of the 16kDa inhibitory form of C/EBP after M. tuberculosis co-infection. Bronchoalveolar lavage cells obtained from normal controls and alveolar macrophages from uninflamed lung of tuberculosis patients also expressed the 16kDa inhibitory form of C/EBP. However, alveolar macrophages from lung segments involved with pulmonary tuberculosis had markedly reduced C/EBP expression. These data suggest that 16kDa isoform of C/EBP plays an important role for the control of HIV-1 replication in macrophages. We propose derepression of HIV-1 LTR mediated transcription as one mechanism for enhanced HIV-1 replication observed in pulmonary tuberculosis. Since the cellular immune response in pulmonary tuberculosis requires lymphocyte/macrophage interaction, a model system was developed in which lymphocytes were added to AM. Contact between lymphocytes and AM reduced inhibitory C/EBP beta, activated NF-kappaB and enhanced HIV-1 replication. If contact between lymphocytes and macrophages was prevented, inhibitory C/EBP beta expression was maintained and the HIV-1 long terminal repeat (LTR) was not maximally stimulated although NF-kappaB was activated. Antibodies which cross-linked macrophage expressed B-7, VCAM and CD-40 were used mimic lymphocyte contact. Cross-linking antibodies abolished inhibitory C/EBP beta expression; however, the HIV-1 LTR was not maximally stimulated and NF-kappaB was not activated. Maximal HIV-1 LTR stimulation required both lymphocyte derived soluble factors and cross-linking of macrophage expressed co-stimulatory molecules. These results demonstrate that neither contact nor soluble factor(s) are sufficient to maximally enhance HIV-1 LTR activity in macrophages. Contact between activated lymphocytes and macrophages is necessary to downregulate inhibitory C/EBP beta, thereby derepressing the HIV-1 LTR. Lymphocyte derived soluble factor(s) activate NF-kappaB, further enhancing the HIV-1 LTR.

AIDS-Related Opportunistic Infections↗