A Quantitative Examination of Illness Models Among People With Opioid Use Disorder Receiving Methadone Treatment.

BACKGROUND: Few studies have examined illness models among people with addiction. We investigated illness models and their associations with demographics and treatment beliefs among patients receiving methadone treatment for opioid use disorder. METHODS: From January 2019 to February 2020, patients receiving methadone treatment at outpatient opioid treatment programs provided demographics and rated using 1 to 7 Likert-type scales agreement with addiction illness models (brain disease model, chronic medical condition model [CMCM], and no explanation [NEM]) and treatment beliefs. Pairwise comparisons and multivariate regressions were used to examine associations between illness models, demographics, and treatment beliefs. Statistical significance was set at P < 0.05. RESULTS: A total of 450 patients participated in the study. Forty percent self-identified as female, 13% as Hispanic, and 78% as White; mean age was 38.5 years. Brain disease model was the most frequently endorsed illness model (46.2%), followed by CMCM (41.7%) and NEM (21.9%). In multivariate analyses, agreement with brain disease model was significantly positively associated with beliefs that methadone treatment would be effective, counseling is important, and methadone is lifesaving, whereas agreement with CMCM was significantly positively associated with beliefs that methadone treatment would be effective, counseling is important, 12-step is the best treatment, taking methadone daily is important, and methadone is lifesaving. In multivariate analyses, agreement with NEM was negatively significantly associated with beliefs that methadone would be effective, counseling is important, taking methadone daily is important, and methadone is lifesaving. DISCUSSION: Many patients in methadone treatment endorsed medicalized addiction models. Agreement with addiction illness models appear to be related to treatment beliefs.

Transgenic Expression of the Vitamin D Receptor Restricted to the Ileum, Cecum, and Colon of Vitamin D Receptor Knockout Mice Rescues Vitamin D Receptor-Dependent Rickets.

Although the intestine plays the major role in 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] action on calcium homeostasis, the mechanisms involved remain incompletely understood. The established model of 1,25(OH)2D3-regulated intestinal calcium absorption postulates a critical role for the duodenum. However, the distal intestine is where 70% to 80% of ingested calcium is absorbed. To test directly the role of 1,25(OH)2D3 and the vitamin D receptor (VDR) in the distal intestine, three independent knockout (KO)/transgenic (TG) lines expressing VDR exclusively in the ileum, cecum, and colon were generated by breeding VDR KO mice with TG mice expressing human VDR (hVDR) under the control of the 9.5-kb caudal type homeobox 2 promoter. Mice from one TG line (KO/TG3) showed low VDR expression in the distal intestine (<50% of the levels observed in KO/TG1, KO/TG2, and wild-type mice). In the KO/TG mice, hVDR was not expressed in the duodenum, jejunum, kidney, or other tissues. Growth arrest, elevated parathyroid hormone level, and hypocalcemia of the VDR KO mice were prevented in mice from KO/TG lines 1 and 2. Microcomputed tomography analysis revealed that the expression of hVDR in the distal intestine of KO/TG1 and KO/TG2 mice rescued the bone defects associated with systemic VDR deficiency, including growth plate abnormalities and altered trabecular and cortical parameters. KO/TG3 mice showed rickets, but less severely than VDR KO mice. These findings show that expression of VDR exclusively in the distal intestine can prevent abnormalities in calcium homeostasis and bone mineralization associated with systemic VDR deficiency.

The Transient Role for Calcium and Vitamin D during the Developmental Hair Follicle Cycle.

The role for 1,25-dihydroxyvitamin D3 and/or calcium in hair follicle cycling is not clear despite their impact on keratinocyte differentiation. We found that calbindin-D9k null (knockout) pups generated from calbindin-D9k knockout females fed a vitamin D-deficient, low-calcium (0.47%) diet develop transient alopecia. The pups appear phenotypically normal until 13 days of age, after which the hair progressively sheds in a caudocephalic direction, resulting in truncal alopecia totalis by 20-23 days, with spontaneous recovery by 28 days. Histological studies showed markedly dystrophic hair follicles, loss of hair shafts with increased apoptosis, and hyperplastic epidermis during this time. Ha1 expression is lost during catagen in all mice but recovers more slowly in the knockout pups on the vitamin D-deficient, low-calcium diet. Keratin 1 expression is reduced throughout days 19-28. The expressions of involucrin, loricrin, and cathepsin L is initially increased by day 19 but subsequently falls below those of controls by day 23, as does that of desmoglein 3. Feeding the mothers a high-vitamin D/high-calcium (2%)/lactose (20%) diet lessens the phenotype, and knockout pups fostered to mothers fed a normal diet do not develop alopecia. Our results show that in calbindin-D9k knockout pups, a maternal vitamin D-deficient/low-calcium diet leads to transient noncicatricial alopecia.